title: Railway air brake

text: In North America, Westinghouse Air Brake supplied High Speed Control brake equipment for several post-World War II streamlined passenger trains. This was an electrically controlled overlay on conventional D-22 passenger and 24-RL locomotive brake equipment. On the conventional side, the control valve set a reference pressure in a volume, which set brake cylinder pressure via a relay valve. On the electric side, pressure from a second straight-air trainline controlled the relay valve via a two-way check valve. This "straight air" trainline was charged "(from reservoirs on each car)" and released by magnet valves on each car, controlled electrically by a 3 wire trainline, in turn controlled by an "electro-pneumatic master controller" in the controlling locomotive. This controller compared the pressure in the straight air trainline with that supplied by a self lapping portion of the engineers valve, signaling all of the "apply" or "release" magnets valves in the train to open simultaneously, changing the pressure in the "straight air" trainline much more rapidly and evenly than possible by simply supplying air directly from the locomotive. The relay valve was equipped with four diaphragms, magnet valves, electric control equipment, and an axle-mounted speed sensor, so that at speeds over full braking force was applied, and reduced in steps at , bringing the train to a gentle stop. Each axle was also equipped with anti-lock brake equipment. The combination minimized braking distances, allowing more full-speed running between stops. The "straight air" "(electro-pneumatic trainline)", anti-lock, and speed graduating portions of the system were not dependent on each other in any way, and any or all of these options could be supplied separately.


title: Railway air brake

text: Later systems replace the automatic air brake with an electrical wire which runs in a circle round the whole train and has to be kept energized to keep the brakes off. In the UK it is known as a "train wire". It is routed through various "governors" (switches operated by air pressure) which monitor critical components such as compressors, brake pipes and air reservoirs. Also if the train divides the wire will be broken, ensuring that all motors are switched off and both portions of the train have an immediate emergency brake application.


title: Railway air brake

text: More recent innovations are electronically controlled pneumatic brakes where the brakes of all the wagons (cars) and locomotives are connected by a kind of local area network, which allows individual control of the brakes on each wagon, and the reporting back of performance of each wagon's brakes.


title: Railway air brake

text: The Westinghouse air brake system is very reliable, but not infallible. The car reservoirs recharge only when the brake pipe pressure is higher than the reservoir pressure. Fully recharging the reservoirs on a long train can require considerable time (8 to 10 minutes in some cases), during which the brake pipe pressure will be lower than locomotive reservoir pressure.


title: Railway air brake

text: If the brakes must be applied before recharging has been completed, a larger brake pipe reduction will be required in order to achieve the desired amount of braking effort, as the system is starting out at a lower point of equilibrium (lower overall pressure). If many brake pipe reductions are made in short succession ("fanning the brake" in railroad slang), a point may be reached where car reservoir pressure will be severely depleted, resulting in substantially reduced brake cylinder piston force, causing the brakes to fail. On a descending grade, the result will be a runaway.


title: Railway air brake

text: In the event of a loss of braking due to reservoir depletion, the engine driver may be able to regain control with an emergency brake application, as the emergency portion of each car's dual-compartment reservoir should be fully charged—it is not affected by normal service reductions. The triple valves detect an emergency reduction based on the "rate" of brake pipe pressure reduction. Therefore, as long as a sufficient volume of air can be rapidly vented from the brake pipe, each car's triple valve will cause an emergency brake application. However, if the brake pipe pressure is too low due to an excessive number of brake applications, an emergency application will not produce a large enough volume of air flow to trip the triple valves, leaving the engine driver with no means to stop the train.


title: Railway air brake

text: To prevent a runaway due to loss of brake pressure, dynamic (rheostatic) braking can be utilized so the locomotive(s) will assist in retarding the train. Often, blended braking, the simultaneous application of dynamic and train brakes, will be used to maintain a safe speed and keep the slack bunched on descending grades. Care would then be given when releasing the service and dynamic brakes to prevent draw-gear damage caused by a sudden run out of the train's slack.


title: Railway air brake

text: Another solution to loss of brake pressure is the two-pipe system, fitted on most locomotive-hauled passenger stock and many freight wagons. In addition to the traditional brake pipe, this enhancement adds the main reservoir pipe, which is continuously charged with air directly from the locomotive's main reservoir. The main reservoir is where the locomotive's air compressor output is stored, and is ultimately the source of compressed air for all systems that use it.


title: Railway air brake

text: Since the main reservoir pipe is kept constantly pressurized by the locomotive, the car reservoirs can be charged independently of the brake pipe, this being accomplished via a check valve to prevent backfeeding into the pipe. This arrangement helps to reduce the above described pressure loss problems, and also reduces the time required for the brakes to release, since the brake pipe only has to recharge itself.


title: Railway air brake

text: Main reservoir pipe pressure can also be used to supply air for auxiliary systems such as pneumatic door operators or air suspension. Nearly all passenger trains (all in the UK and USA), and many freights, now have the two-pipe system.


title: Railway air brake

text: At both ends of each car, there are "angle cocks" fitted. These valves cut off the air from the train line and vent the coupling hoses for uncoupling cars. The air brake only operates if the angle cocks are open except the ones at the front of the locomotive and at the end of the train.


title: Railway air brake

text: The air brake can fail if one of the angle cocks is accidentally closed. In this case, the brakes on the wagons behind the closed cock will fail to respond to the driver's command. This happened in the 1953 Pennsylvania Railroad train wreck involving the "Federal Express", a Pennsylvania Railroad train which became runaway while heading into Washington DC's Union Station, causing the train to crash into the passenger concourse and fall through the floor. Similarly, in the Gare de Lyon rail accident, a valve was accidentally closed by the crew, reducing braking power.


title: Railway air brake

text: There are a number of safeguards that are usually taken to prevent this sort of accident happening. Railroads have strict government-approved procedures for testing the air brake systems when making up trains in a yard or picking up cars en route. These generally involve connecting the air brake hoses, charging up the brake system, setting the brakes and manually inspecting the cars to ensure the brakes are applied, and then releasing the brakes and manually inspecting the cars to ensure the brakes are released. Particular attention is usually paid to the rearmost car of the train, either by manual inspection or via an automated end-of-train device, to ensure that brake pipe continuity exists throughout the entire train. When brake pipe continuity exists throughout the train, failure of the brakes to apply or release on one or more cars is an indication that the cars' triple valves are malfunctioning. Depending on the location of the air test, the repair facilities available, and regulations governing the number of inoperative brakes permitted in a train, the car may be set out for repair or taken to the next terminal where it can be repaired.


title: Railway air brake

text: The modern air brake is not identical with the original airbrake as there have been slight changes in the design of the triple valve, which are not completely compatible between versions, and which must therefore be introduced in phases. However, the basic air brakes used on railways worldwide are remarkably compatible.


title: Railway air brake

text: European railway air brakes include the Kunze-Knorr brake (invented by Georg Knorr and manufactured by Knorr-Bremse) and the Oerlikon. The working principle is the same as for the Westinghouse air brake. In the steam era, Britain's railways were divided – some using vacuum brakes and some using air brakes – but there was a gradual standardization on the vacuum brake. Some locomotives, e.g. on the London, Brighton and South Coast Railway, were dual-fitted so that they could work with either vacuum- or air-braked trains. In the diesel era, the process was reversed and British Railways switched from vacuum-braked to air-braked rolling stock in the 1960s.


title: Railway air brake

text: The main competitor to the air brake is the vacuum brake, which operates on negative pressure. The vacuum brake is a little simpler than the air brake. Instead of an air compressor, steam engines have an ejector with no moving parts, and diesel or electric locomotives have a mechanical or electrical "exhauster". Disconnection taps at the ends of cars are not required because the loose hoses are sucked onto a mounting block.


title: Railway air brake

text: However, the maximum pressure in a vacuum system is limited to atmospheric pressure, so all the equipment has to be much larger and heavier to compensate. That disadvantage is made worse at high altitude. The vacuum brake is also considerably slower to both apply and release the brake, which requires a greater level of skill and anticipation from the driver. Conversely, the vacuum brake originally had the advantage of allowing gradual release, whereas the Westinghouse automatic air brake was originally available in only the direct-release form still common in freight service.


title: Railway air brake

text: A primary fault of vacuum brakes is the inability to find leaks easily. In a positive air system, a leak is quickly found due to the escaping pressurized air. Discovering a vacuum leak is more difficult, although it is easier to repair, because a piece of rubber (for example) can just be tied around the leak and will be firmly held in place by the vacuum.


title: Railway air brake

text: Electro-vacuum brakes have been used with considerable success on South African electric multiple unit trains. Despite requiring larger and heavier equipment, as stated above, the performance of the electro-vacuum brake approached that of contemporary electro-pneumatic brakes. However, their use has not been repeated.


title: Vaivasvata Manu

text: Vaivasvata Manu (), also referred to as Shraddhadeva and Satyavrata, is the current Manu—the progenitor of the human race in Hindu mythology. He is the seventh of the 14 Manus of the current kalpa (aeon) of Hindu cosmology.


title: Vaivasvata Manu

text: Forewarned about the divine flood by the Matsya avatara of Vishnu, he saved mankind by building a boat that carried his family and the Saptarishi to safety. He is the son of Vivasvana.


title: Vaivasvata Manu

text: Shraddhadeva is stated to be the king of the Dravida Kingdom during the epoch of the "Matsya Purana". According to the "Matsya Purana", Matsya, the avatara of Vishnu, first appeared as a "shaphari" (a small carp) to Shraddhadeva while he washed his hands in a river flowing down the Malaya Mountains.


title: Vaivasvata Manu

text: The little fish asked the king to save him, and out of compassion, he put it in a water jar. It kept growing bigger and bigger, until the king first put it in a bigger pitcher, and then deposited it in a well. When the well also proved insufficient for the ever-growing fish, the king placed it in a tank (reservoir), that was two yojanas (16 miles) in height above the surface and on land, as much in length, and a yojana (8 miles) in breadth. As it grew further, the king had to put the fish in a river, and when even the river proved insufficient, he placed it in the ocean, after which it nearly filled the vast expanse of the great ocean.


title: Vaivasvata Manu

text: It was then that Vishnu, revealing himself, informed the king of an all-destructive deluge which would be coming very soon. The king built a huge boat which housed his family, saptarishi, nine types of seeds, and animals to repopulate the earth, after the deluge would end and the oceans and seas would recede. At the time of deluge, Vishnu appeared as a horned fish and Shesha appeared as a rope, with which the king fastened the boat to the horn of the fish.


title: Vaivasvata Manu

text: The boat was perched after the deluge on the top of the highest peak of Himavat called Naubandhana. After the deluge, Manu's family and the seven sages repopulated the earth. According to Purana, Manu's story occur before 28 chaturyuga in the present Manvantara which is the 7th Manvantara. This amounts to 120 million years ago.


title: Vaivasvata Manu

text: This narrative is similar to other flood myths like the Gilgamesh flood myth and the Genesis flood narrative.


title: Vaivasvata Manu

text: Shraddhadeva married Shraddha and had ten children including Ila and Ikshvaku, the progenitors of the Lunar and Solar dynasties, respectively.


title: Vaivasvata Manu

text: In Theosophy, the "Vaivasvata Manu" is one of the most important beings at the highest level of Initiation of the ancient Vedic sages, along with Maitreya, and the Maha Chohan. According to Theosophy, each root race has its own Manu who physically incarnates in an advanced body of an individual of the old root race and physically progenerates with a suitable female partner the first individuals of the new root race.


title: PowerVR

text: PowerVR is a division of Imagination Technologies (formerly VideoLogic) that develops hardware and software for 2D and 3D rendering, and for video encoding, decoding, associated image processing and DirectX, OpenGL ES, OpenVG, and OpenCL acceleration. PowerVR also develops AI accelerators called Neural Network Accelerator (NNA).


title: PowerVR

text: The PowerVR product line was originally introduced to compete in the desktop PC market for 3D hardware accelerators with a product with a better price–performance ratio than existing products like those from 3dfx Interactive. Rapid changes in that market, notably with the introduction of OpenGL and Direct3D, led to rapid consolidation. PowerVR introduced new versions with low-power electronics that were aimed at the laptop computer market. Over time, this developed into a series of designs that could be incorporated into system-on-a-chip architectures suitable for handheld device use.


title: PowerVR

text: PowerVR accelerators are not manufactured by PowerVR, but instead their integrated circuit designs and patents are licensed to other companies, such as Texas Instruments, Intel, NEC, BlackBerry, Renesas, Samsung, STMicroelectronics, Freescale, Apple (Imagination Technologies signed a new multi-year, multi-lease agreement under which Apple has access to a wider range of Imagination’s intellectual property in exchange for license fees on January 2, 2020. The re-kindling of the partnership between the two companies comes as Apple's licences to Imagination graphics IP expire at the end of 2019.), NXP Semiconductors (formerly Philips Semiconductors), and many others.


title: PowerVR

text: The PowerVR chipset uses a method of 3D rendering known as "tile-based deferred rendering" (often abbreviated as TBDR) which is tile-based rendering combined with PowerVR's proprietary method of Hidden Surface Removal (HSR) and Hierarchical Scheduling Technology (HST). As the polygon generating program feeds triangles to the PowerVR (driver), it stores them in memory in a triangle strip or an indexed format. Unlike other architectures, polygon rendering is (usually) not performed until all polygon information has been collated for the current frame. Furthermore, the expensive operations of texturing and shading of pixels (or fragments) is delayed, whenever possible, until the visible surface at a pixel is determined — hence rendering is deferred.


title: PowerVR

text: In order to render, the display is split into rectangular sections in a grid pattern. Each section is known as a tile. Associated with each tile is a list of the triangles that visibly overlap that tile. Each tile is rendered in turn to produce the final image.


title: PowerVR

text: Tiles are rendered using a process similar to ray-casting. Rays are numerically simulated as if cast onto the triangles associated with the tile and a pixel is rendered from the triangle closest to the camera. The PowerVR hardware typically calculates the depths associated with each polygon for one tile row in 1 cycle.


title: PowerVR

text: This method has the advantage that, unlike a more traditional early Z rejection based hierarchical systems, no calculations need to be made to determine what a polygon looks like in an area where it is obscured by other geometry. It also allows for correct rendering of partially transparent polygons, independent of the order in which they are processed by the polygon producing application. (This capability was only implemented in Series 2 including Dreamcast and one MBX variant. It is generally not included for lack of API support and cost reasons.)


title: PowerVR

text: More importantly, as the rendering is limited to one tile at a time, the whole tile can be in fast on-chip memory, which is flushed to video memory before processing the next tile. Under normal circumstances, each tile is visited just once per frame.


title: PowerVR

text: PowerVR is a pioneer of tile based deferred rendering. Microsoft also conceptualized the idea with their abandoned Talisman project. Gigapixel, a company that developed IP for tile-based 3D graphics, was purchased by 3dfx, which in turn was subsequently purchased by Nvidia. Nvidia has now been shown to use tile rendering in the Maxwell and Pascal microarchitectures for a limited amount of geometry.


title: PowerVR

text: ARM began developing another major tile based architecture known as Mali after their acquisition of Falanx.


title: PowerVR

text: Intel uses a similar concept in their integrated graphics products. However, its method, called zone rendering, does not perform full hidden surface removal (HSR) and deferred texturing, therefore wasting fillrate and texture bandwidth on pixels that are not visible in the final image.


title: PowerVR

text: Recent advances in hierarchical Z-buffering have effectively incorporated ideas previously only used in deferred rendering, including the idea of being able to split a scene into tiles and of potentially being able to accept or reject tile sized pieces of polygon.


title: PowerVR

text: Today, the PowerVR software and hardware suite has ASICs for video encoding, decoding and associated image processing. It also has virtualisation, and DirectX, OpenGL ES, OpenVG, and OpenCL acceleration.


title: PowerVR

text: Newest PowerVR Wizard GPUs have fixed-function Ray Tracing Unit (RTU) hardware and support hybrid rendering.


title: PowerVR

text: The first series of PowerVR cards was mostly designed as 3D-only accelerator boards that would use the main 2D video card's memory as framebuffer over PCI. Videologic's first PowerVR PC product to market was the 3-chip Midas3, which saw very limited availability in some OEM Compaq PCs. This card had very poor compatibility with all but the first Direct3D games, and even most SGL games did not run. However, its internal 24-bit color precision rendering was notable for the time.


title: PowerVR

text: The single-chip PCX1 was released in retail as the VideoLogic Apocalypse 3D and featured an improved architecture with more texture memory, ensuring better game compatibility. This was followed by the further refined PCX2, which clocked 6 MHz higher, offloaded some driver work by including more chip functionality and added bilinear filtering, and was released in retail on the Matrox M3D and Videologic Apocalypse 3Dx cards. There was also the Videologic Apocalypse 5D Sonic, which combined the PCX2 accelerator with a Tseng ET6100 2D core and ESS Agogo sound on a single PCI board.


title: PowerVR

text: The PowerVR PCX cards were placed in the market as budget products and performed well in the games of their time, but weren't quite as fully featured as the 3DFX Voodoo accelerators (due to certain blending modes being unavailable, for instance). However, the PowerVR approach of rendering to the 2D card's memory meant that much higher 3D rendering resolutions could be possible in theory, especially with PowerSGL games that took full advantage of the hardware.


title: PowerVR

text: The second generation PowerVR2 ("PowerVR Series2", chip codename "CLX2") was brought to market in the Dreamcast console between 1998 and 2001. As part of an internal competition at Sega to design the successor to the Saturn, the PowerVR2 was licensed to NEC and was chosen ahead of a rival design based on the 3dfx Voodoo2. It was called "the Highlander Project" during development. The PowerVR2 was paired with the Hitachi SH-4 in the Dreamcast, with the SH-4 as the T&L geometry engine and the PowerVR2 as the rendering engine. The PowerVR2 also powered the Sega Naomi, the upgraded arcade system board counterpart of the Dreamcast.


title: PowerVR

text: However, the success of the Dreamcast meant that the PC variant, sold as Neon 250, appeared a year late to the market, in late 1999. The Neon 250 was nevertheless competitive with the RIVA TNT2 and Voodoo3. The Neon 250 features inferior hardware specifications compared to the PowerVR2 part used in Dreamcast, such as a halved tile size, among others.


title: PowerVR

text: In 2000, the third generation PowerVR3 STG4000 "KYRO" was released, manufactured by new partner STMicroelectronics. The architecture was redesigned for better game compatibility and expanded to a dual-pipeline design for more performance. The refresh STM PowerVR3 KYRO II, released later in 2001, likely had a lengthened pipeline to attain higher clock speeds and was able to rival the more expensive ATI Radeon DDR and NVIDIA GeForce 2 GTS in some benchmarks of the time, despite its modest specifications on paper and lack of hardware transform and lighting (T&L), a fact that Nvidia especially tried to capitalize on in a confidential paper they sent out to reviewers. As games increasingly started to include more geometry with this feature in mind, the KYRO II lost its competitiveness.


title: PowerVR

text: The KYRO series had a decent featureset for a budget-oriented GPU in their time, including a few Direct3D 8.1-compliant features such as 8-layer multitexturing (not 8-pass) and Environment Mapped Bump Mapping (EMBM); Full Scene Anti-Aliasing (FSAA) and Trilinear/Anisotropic filtering were also present. KYRO II could also perform Dot Product (Dot3) Bump Mapping at a similar speed as GeForce 2 GTS in benchmarks. Omissions included hardware T&L (an optional feature in Direct3D 7), Cube Environment Mapping and legacy 8-bit paletted texture support. While the chip supported S3TC/DXTC texture compression, only the (most commonly used) DXT1 format was supported. Support for the proprietary PowerSGL API was also dropped with this series.


title: PowerVR

text: 16-bit output quality was excellent compared to most of its competitors, thanks to rendering to its internal 32-bit tile cache and downsampling to 16-bit instead of straight use of a 16-bit framebuffer. This could play a role in improving performance without losing much image quality, as memory bandwidth was not plentiful. However, due to its unique concept on the market, the architecture could sometimes exhibit flaws such as missing geometry in games, and therefore the driver had a notable amount of compatibility settings, such as switching off the internal Z-buffer. These settings could cause a negative impact on performance.


title: PowerVR

text: A second refresh of the KYRO was planned for 2002, the STG4800 KYRO II SE. Samples of this card were sent to reviewers but it does not appear to have been brought to market. Apart from a clockspeed boost, this refresh was announced with a "EnT&L" HW T&L software emulation, which eventually made it into the drivers for the previous KYRO cards starting with version 2.0. The STG5500 KYRO III, based upon the next-generation PowerVR4, was completed and would have included hardware T&L but was shelved due to STMicro closing its graphics division.


title: PowerVR

text: PowerVR achieved great success in the mobile graphics market with its low power PowerVR MBX. MBX, and its SGX successors, are licensed by seven of the top ten semiconductor manufacturers including Intel, Texas Instruments, Samsung, NEC, NXP Semiconductors, Freescale, Renesas and Sunplus. The chips were used in many high-end cellphones including the original iPhone and iPod Touch, Nokia N95, Sony Ericsson P1 and Motorola RIZR Z8. It was also used in some PDA's such as the Dell Axim X50V and X51V featuring the MBX Lite powered Intel 2700G, as well as in set-top boxes featuring the MBX Lite-powered Intel CE 2110.


title: PowerVR

text: There are two variants: MBX and MBX Lite. Both have the same feature set. MBX is optimized for speed and MBX Lite is optimized for low power consumption. MBX could be paired up with an FPU, Lite FPU, VGP Lite and VGP.


title: PowerVR

text: PowerVR's Series5 SGX series features pixel, vertex, and geometry shader hardware, supporting OpenGL ES 2.0 and DirectX 10.1 with Shader Model 4.1.


title: PowerVR

text: The SGX GPU core is included in several popular systems-on-chip (SoC) used in many portable devices. Apple uses the A4 (manufactured by Samsung) in their iPhone 4, iPad, iPod Touch, and Apple TV, and uses the Apple S1 in the Apple Watch. Texas Instruments' OMAP 3 and 4 series SoC's are used in the Amazon's Kindle Fire HD 8.9", Barnes and Noble's Nook HD(+), BlackBerry PlayBook, Nokia N9, Nokia N900, Sony Ericsson Vivaz, Motorola Droid/Milestone, Motorola Defy, Motorola RAZR D1/D3, Droid Bionic, Archos 70, Palm Pre, Samsung Galaxy SL, Galaxy Nexus, Open Pandora, and others. Samsung produces the "Hummingbird" SoC and uses it in their Samsung Galaxy S, Galaxy Tab, Samsung Wave S8500 Samsung Wave II S8530 and Samsung Wave III S860 devices. Hummingbird is also in Meizu M9 smartphone.


title: PowerVR

text: PowerVR Series5XT SGX chips are multi-core variants of the SGX series with some updates. It is included in the PlayStation Vita portable gaming device with the MP4+ Model of the PowerVR SGX543, the only intended difference, aside from the + indicating features customized for Sony, is the cores, where MP4 denotes 4 cores (quad-core) whereas the MP8 denotes 8 cores (octo-core). The Allwinner A31 (quad-core mobile application processor) features the dual-core SGX544 MP2. The Apple iPad 2 and iPhone 4S with the A5 SoC also feature a dual-core SGX543MP2. The iPad (3rd generation) A5X SoC features the quad-core SGX543MP4. The iPhone 5 A6 SoC features the tri-core SGX543MP3. The iPad (4th generation) A6X SoC features the quad-core SGX554MP4. The Exynos variant of the Samsung Galaxy S4 sports the tri-core SGX544MP3 clocked at 533 MHz.


title: PowerVR

text: Introduced in 2014, the PowerVR GX5300 GPU is based on the SGX architecture and is the world's smallest Android-capable graphics core, providing low-power products for entry-level smartphones, wearables, IoT and other small footprint embedded applications, including enterprise devices such as printers.


title: PowerVR

text: PowerVR Series6 GPUs are based on an evolution of the SGX architecture codenamed "Rogue". ST-Ericsson (now defunct) announced that its Nova application processors would include Imagination's next-generation PowerVR Series6 architecture. MediaTek announced the quad-core MT8135 system on a chip (SoC) (two ARM Cortex-A15 and two ARM Cortex-A7 cores) for tablets. Renesas announced its R-Car H2 SoC includes the G6400. Allwinner Technology A80 SoC, (4 Cortex-A15 and 4 Cortex-A7) that is available in the Onda V989 tablet, features a PowerVR G6230 GPU. The Apple A7 SoC integrates a graphics processing unit (GPU) which AnandTech believes to be a PowerVR G6430 in a four cluster configuration.


title: PowerVR

text: PowerVR Series6XE GPUs are based around Series6 and designed as entry-level chips aimed at offering roughly the same fillrate compared to the Series5XT series. They however feature refreshed API support such as Vulkan, OpenGL ES 3.1, OpenCL 1.2 and DirectX 9.3 (9.3 L3). Rockchip and Realtek have used Series6XE GPUs in their SoCs.


title: PowerVR

text: PowerVR Series6XT GPUs aims at reducing power consumption further through die area and performance optimization providing a boost of up to 50% compared to Series6 GPUs. Those chips sport PVR3C triple compression system-level optimizations and Ultra HD deep color. The Apple iPhone 6, iPhone 6 Plus and iPod Touch (6th generation) with the A8 SoC feature the quad-core GX6450. An unannounced 8 cluster variant was used in the Apple A8X SoC for their iPad Air 2 model (released in 2014). The MediaTek MT8173 and Renesas R-Car H3 SoCs use Series6XT GPUs.


title: PowerVR

text: PowerVR Series 7XE GPUs were announced on 10 November 2014. When announced, the 7XE series contained the smallest Android Extension Pack compliant GPU.


title: PowerVR

text: PowerVR Series7XT GPUs are available in configurations ranging from two to 16 clusters, offering dramatically scalable performance from 100 GFLOPS to 1.5 TFLOPS. The GT7600 is used in the Apple iPhone 6s and iPhone 6s Plus models (released in 2015) as well as the Apple iPhone SE model (released in 2016) and the Apple iPad model (released in 2017) respectively. An unannounced 12 cluster variant was used in the Apple A9X SoC for their iPad Pro models (released in 2015).


title: PowerVR

text: PowerVR Series7XT Plus GPUs are an evolution of the Series7XT family and add specific features designed to accelerate computer vision on mobile and embedded devices, including new INT16 and INT8 data paths that boost performance by up to 4x for OpenVX kernels. Further improvements in shared virtual memory also enable OpenCL 2.0 support. The GT7600 Plus is used in the Apple iPhone 7 and iPhone 7 Plus models (released in 2016) as well as the Apple iPad model (released in 2018).


title: PowerVR

text: The GPUs are designed to offer improved in-system efficiency, improved power efficiency and reduced bandwidth for vision and computational photography in consumer devices, mid-range and mainstream smartphones, tablets and automotive systems such as advanced driver assistance systems (ADAS), infotainment, computer vision and advanced processing for instrument clusters.


title: PowerVR

text: Up to 4x higher performance for OpenVX/vision algorithms compared to the previous generation through improved integer (INT) performance (2x INT16; 4x INT8)


title: PowerVR

text: Dynamic parallelism for more efficient execution and control through support for device enqueue in OpenCL 2.0


title: PowerVR

text: PowerVR Series8XE GPUs support OpenGL ES 3.2 and Vulkan 1.x and are available in 1, 2, 4 and 8 pixel/clock configurations, enabling the latest games and apps and further driving down the cost of high quality UIs on cost sensitive devices.


title: PowerVR

text: PowerVR Series 8XE were announced February 22, 2016 at the Mobile World Congress 2016. They are an iteration of the Rogue microarchitecture and target entry-level SoC GPU market.


title: PowerVR

text: New GPUs improve the performance/mm2 for the smallest silicon footprint and power profile, while also incorporating hardware virtualization and multi-domain security. Newer model were later released in January 2017, with a new low end and high end part.


title: PowerVR

text: PowerVR Series8XEP were announced January 2017. There are an iteration of the Rogue microarchitecture and target the mid range SoC GPU market, targeting 1080p. The Series8XEP remains focused on die size and performance per unit


title: PowerVR

text: Announced on 8 March 2017, Furian is the first new PowerVR architecture since Rogue was introduced five years earlier.


title: PowerVR

text: PowerVR Series 8XT were announced March 8, 2017. It's the first series GPU's based on the new Furian architecture. According to Imagination, GFLOPS/mm2 is improved 35% and Fill rate/mm is improved 80% compared to the 7XT Plus series on the same node. Specific designs aren't announced as of March 2017. Series8XT features 32-wide pipeline clusters.


title: PowerVR

text: Announced in September 2017, Series9XE family of GPUs benefit from up to 25% Bandwidth savings over the previous generation GPUs. The Series9XE family is targeted for set-top boxes (STB), digital TVs (DTV) and low end smartphones SoCs


title: PowerVR

text: The Series9XM family of GPUs achieve up to 50% better performance density than the previous 8XEP generation. The Series9XM family targets mid-range smartphone SoCs.


title: PowerVR

text: The Series9XEP family of GPUs was announced on December 4, 2018. The Series9XEP family supports PVRIC4 image compression. The Series9XEP family targets set-top boxes (STB), digital TVs (DTV) and low end smartphones SoCs.


title: PowerVR

text: The Series9XMP family of GPUs was announced on December 4, 2018. The Series9XMP family supports PVRIC4 image compression. The Series9XMP family targets mid-range smartphone SoCs.


title: PowerVR

text: The Series9XTP family of GPUs was announced on December 4, 2018. The Series9XTP family supports PVRIC4 image compression. The Series9XTP family targets high-end smartphone SoCs. Series9XTP features 40-wide pipeline clusters.


title: PowerVR

text: The A-Series GPUs offer up to 250% better performance density than the previous Series 9. These GPUs are no longer called PowerVR, they are called IMG.


title: PowerVR

text: The Series3NX-F family of Neural Network Accelerators (NNA) was announced alongside the Series3NX family. The Series3NX-F family combines the Series 3NX with a Rogue-based GPGPU (NNPU), and local RAM. This allows support for programmability and floating-point.


title: PowerVR

text: The PowerVR GPU variants can be found in the following table of systems on chips (SoC). Implementations of PowerVR accelerators in products are listed here.


title: Chatham, Kent

text: Chatham ( ) is a town located within the Medway unitary authority in the ceremonial county of Kent, England. The town forms a conurbation with neighbouring towns Gillingham, Rochester, Strood and Rainham.


title: Chatham, Kent

text: The town developed around Chatham Dockyard and several Army barracks, together with 19th-century forts which provided a defensive shield for the dockyard. The Corps of Royal Engineers is still based in Chatham at Brompton Barracks.


title: Chatham, Kent

text: The Dockyard closed in 1984, but the remaining major naval buildings are an attraction for a flourishing tourist industry. Following closure, part of the site was developed as a commercial port, other parts were redeveloped for business and residential use, and part was used as the Chatham Historic Dockyard museum. Its attractions include the submarine .


title: Chatham, Kent

text: The town has important road links and the railway and bus stations are the main interchanges for the area. It is the administrative headquarters of Medway unitary authority, as well as its principal shopping centre.


title: Chatham, Kent

text: The name "Chatham" was first recorded as "Cetham" in 880. The Domesday Book records the place as "Ceteham".


title: Chatham, Kent

text: Most books explain this name as a British root "ceto" (like Welsh "coed"), plus Old English "ham", meaning a forest settlement.


title: Chatham, Kent

text: The river-valley site of Chatham is, however, more consistent with "cet" being an Old English survival of the element "catu", that was common in Roman-era names and meant 'basin' or 'valley'.


title: Chatham, Kent

text: The A2 road passes by Chatham along the line of the ancient Celtic route. It was paved by the Romans, and named Watling Street by the Anglo-Saxons. Among archaeological finds here have been the remains of a Roman-era cemetery.


title: Chatham, Kent

text: Chatham was long a small village on the banks of the river. By the 16th century, warships were being moored at Jillingham water (Gillingham), because of its strategic sheltered location between London and the Continent. It was established as a Royal Dockyard by Queen Elizabeth I in 1568, and most of the dockyard lies within Gillingham. Initially a refitting base, it became a shipbuilding yard; from then until the late 19th century, further expansion of the yard took place. In its time, many thousands of men were employed at the dockyard, and many hundreds of vessels were launched there, including "HMS Victory," which was built there in the 1760s. After World War I, many submarines were also built in Chatham Dockyard.


title: Chatham, Kent

text: In addition to the dockyard, defensive fortifications were built to protect it from attack. Upnor Castle had been built in 1567, but had proved ineffectual; the Dutch raid on the Medway in 1667 showed that more defences were required. The fortifications, which became more elaborate as the threat of invasion grew, were begun in 1756 as a complex across the neck of the peninsula formed by the bend in the River Medway, and included Fort Amherst. The threat of a land-based attack from the south during the 19th century led to the construction of more forts.


title: Chatham, Kent

text: The second phase of fort-building (1806–1819) included Fort Pitt (later used as a hospital and the site of the first Army Medical School). The 1859 Royal Commission on the Defence of the United Kingdom ordered, "inter alia", a third outer ring of forts: these included Fort Luton, Fort Bridgewood, and Fort Borstal.


title: Chatham, Kent

text: These fortifications all required military personnel to man them and Army barracks to house those men. These included Kitchener Barracks (c 1750–1780), the Royal Marine Barracks (c 1780), Brompton Artillery Barracks (1806) and Melville Barracks (opened 1820 as a Naval hospital, RM barracks from 1905). H.M.S. Collingwood and H.M.S. Pembroke were both naval barracks.


title: Chatham, Kent

text: In response to the huge manpower needs, the village of Chatham and other nearby villages and towns grew commensurately. Trams, and later buses, linked those places to bring in the workforce. The area between the High Street and Luton village illustrates part of that growth, with its many streets of Victorian terraces.


title: Chatham, Kent

text: The importance of Chatham Dockyard gradually declined as Britain's naval resources were reduced or moved to other locations, and eventually, on the 31st March 1984, it was closed completely. The dockyard buildings were preserved as the historic site Chatham Historic Dockyard (operated by Chatham Historic Dockyard Trust), which was under consideration as a World Heritage Site the site is being used for other purposes. Part of the St Mary's Island section is now used as a marina, and the remainder is being developed for housing, commercial and other uses, branded as "Chatham Maritime".


title: Chatham, Kent

text: Chatham lost its independence as a borough under the Local Government Act 1972, by which, on 1 April 1974, it became part of the Borough of Medway, a non-metropolitan district of the county of Kent; under subsequent renaming the Borough became the Borough of Rochester-upon-Medway (1979); and, from 1982, the City of Rochester-upon-Medway. Under the most recent change, in 1998, and with the addition of the Borough of Gillingham, the Borough of Medway became a unitary authority area, administratively separate from Kent. It remains part of the county of Kent for ceremonial purposes.


title: Chatham, Kent

text: Medway Council has recently relocated its main administration building to Gun Wharf, the site of the earliest part of the Dockyard, a former Lloyd's office building. It was built between 1976 and 1978 and is Grade II listed.


title: Chatham, Kent

text: Chatham is currently part of the parliamentary constituency of Chatham and Aylesford. Prior to 1997, Chatham had been included in the constituencies of Mid Kent, Rochester and Chatham and Chatham.


title: Chatham, Kent

text: Chatham has proven to be a marginal parliamentary seat. Since 1945, the members of parliament for Chatham have been as follows:


title: Chatham, Kent

text: Chatham is situated where the lower part of the dip slope of the North Downs meets the River Medway which at this point is flowing in a south–north direction. This gives the right bank, where the town stands, considerable advantages from the point of view of river use. Compared with opposite bank, the river is fast-flowing and deep; the illustration (1), an early print of the settlement, is taken from the point where Fort Pitt now stands. The town lies below at river level, curving round to occupy a south-easterly trending valley (The Brook"), in which lies the High Street. Beyond the Chatham Dockyard was marshy land, now called St Mary's Island, and has several new developments of housing estates. The New Road crosses the scene below the vantage point of the illustration.


title: Chatham, Kent

text: Illustration (2) is taken from the opposite side of the valley: the Pentagon Shopping Centre is to the right, with the building on the ridge left of centre, Fort Pitt and Rochester lies beyond that ridge; and Frindsbury is on the rising ground in the right distance.


title: Chatham, Kent

text: The valley continues southeastwards as the Luton Valley, in which is the erstwhile village of that name; and Capstone Valley. The "Darland Banks", the northern slopes of the Luton Valley above these valleys, are unimproved chalk grassland. The photograph (3), taken from the Banks and looking south, shows the village in the centre, with the rows of Victorian terraced housing, which unusually follow the contour lines. The opposite slopes are the ‘’Daisy Banks'’ and ‘’Coney Banks'’, along which some of the defensive forts were built (including Fort Luton, in the trees to the left)


title: Chatham, Kent

text: Until the start of the 20th century, most of the south part of the borough was entirely rural, with a number of farms and large tracts of woodland. The beginning of what is now Walderslade was when a speculative builder began to build the core of the village in "Walderslade Bottoms".


title: Chatham, Kent

text: Chatham became a market town in its own right in the 19th century, and a municipal borough in 1890. By 1831 its population had reached more than 16,000. By 1961 it had reached 48,800.


title: Chatham, Kent

text: The closure of the Royal Navy Dockyard on the 31st March 1984 had the effect of changing the employment statistics of the town. About 7,000 people lost their jobs. The unemployment rate went up to 23.5%. From early April 1984 to December 1985, and onwards, the Medway Towns began to have an increase in alcohol and drug related, anti-social behaviour, which many residents then realized had largely been caused by the closure of the Royal Navy Dockyard in 1984, and the resulting mass redundancies which occurred. There has been a concerted effort to revitalise the Thames Gateway area and one of the largest employers in Chatham is now Vanquis Bank Ltd, a subsidiary of Provident Financial.


title: Chatham, Kent

text: The Chatham Naval Memorial commemorates the 18,500 officers, ranks and ratings of the Royal Navy who were lost or buried at sea in World War One and World War Two. The Chatham Naval Memorial was originally constructed from March 1924 to October 1924. The addition of the obelisk and Portland Stone plaque walls and surroundings were constructed between June 1952 to October 1952. It stands on the Great Lines, the escarpment ridge between Chatham and Gillingham. The Grade II listed building Chatham Town Hall was built in January 1900; it stands in The Brook, and is of a unique architectural design. With Chatham being part of the Medway Towns, it took on a new role as the Medway Arts Centre in April 1987, with the promotional motto ""Putting The Arts Back Into The Medway"". There were many events held within the Medway Arts Centre, including many stage plays, themed nights and snooker tournaments. Likewise during May 1990, the Medway Arts Centre organized a large parade, composed of dancers, musicians, artists and sculptors, who stood upon theatrical lorry floats. The vehicles were initially parked up next to the entrance into the Theatre Royal Cafe, that was a popular restaurant in the Chatham Town Hall, on Whiffens Avenue, and then started to travel into Chatham, Rochester, Strood and Frindsbury, where sweets, chocolate, posters, badges, leaflets, stickers and t-shirts were handed out to the crowds, to promote the Medway Arts Centre. Then in April 1997, the Medway Arts Centre became the "Brook Theatre". The Pentagon Shopping Centre stands in the town centre and serviced the old Pentagon Bus Station that was closed in September 2011. Chatham Waterfront bus station opened in October 2011, replacing the town's previous Pentagon Bus Station which was opened in 1970, before the Pentagon Shopping Centre was opened in 1975, and was considered an unwelcoming environment for passengers. This was because of the diesel fumes from the buses, coaches and minibuses, and because the waiting areas would sometimes become very crowded, whenever large groups of customers from the Pentagon Shopping Centre used the stairs and escalators, to get on board the green buses, coaches and minibuses that were managed by Maidstone & District Motor Services.


title: Chatham, Kent

text: The Medway, apart from Chatham Dockyard, has always had an important role in communication: historically it provided a means for the transport of goods to and from the interior of Kent. Stone, timber and iron from the Weald for shipbuilding and agricultural produce were among the cargoes. Sun Pier in Chatham was one of many such along the river. By 1740, barges of forty tons could navigate as far upstream as Tonbridge. Today its use is confined to tourist traffic; apart from the marina, there are many yacht moorings on the river itself.


title: Chatham, Kent

text: The position of the road network in Chatham began with the building of the Roman road (Watling Street, which passed through the town. Turnpike trusts were established locally, so that the length from Chatham to Canterbury was turnpiked in 1730; and the Chatham to Maidstone road (now the A230) was also turnpiked before 1750. The High Street was bypassed in 1769, by the "New Road" (see illustration (1)) leading from the top of Star Hill Rochester, to the bottom of Chatham Hill at Luton Arches. This also became inadequate for the London cross-channel traffic and the "Medway Towns Bypass", the M2 motorway, was constructed to divert through traffic south of the Medway Towns.


title: Chatham, Kent

text: Chatham is the hub of the Medway Towns. This fact means that the existing road system has always proved inadequate for the amount of traffic it has to handle, and various schemes have been tried by Rochester-Upon-Medway City Council, to alleviate the congestion. The High Street itself is traffic free, so all traffic on Best Street and Railway Street has to skirt around it. The basic west–east routes are The Brook to the north and New Road to the south, but the additional problems caused by the situation of the Pentagon Bus Station meant that conflicting traffic flows were the result, from 1975 and onward. From April 1986 and onward until October 1987, the town centre remodelling of Chatham began, and Railway Street was realigned into becoming part of an inner ring road, that became a one-way system. This redevelopment included the demolition of the House Of Holland department store in January 1987, and the construction of the "Sir John Hawkins Flyover" in Chatham, that was opened in February 1989, so the traffic could be carried from south to north over the High Street.


title: Chatham, Kent

text: In September 2006, the one-way system was abandoned and two-way traffic reintroduced on most of the ring-road system. Further work on the road system commenced early in 2009, and as of early 2010, the demolition of the "Sir John Hawkins Flyover" has been completed. It was replaced by a street-level, buses only, road coupled with repositioning of the bus station. The new Waterfront bus station opened in October 2011.


title: Chatham, Kent

text: Chatham railway station, opened in 1858, serves both the North Kent and the Chatham Main Lines, and is the interchange between the two lines. It lies in the valley between the Fort Pitt and the Chatham Tunnels. There are three trains an hour to London Victoria, two trains an hour to London Charing Cross, two trains an hour to Luton (via London Bridge, St Pancras and Luton Airport Parkway) and two services an hour to St Pancras via High Speed 1. The former services run to Dover and Ramsgate; the Charing Cross services terminate at Gillingham and the High Speed services terminate at Faversham.


title: Chatham, Kent

text: Part of the industrial railway in what is now Chatham Historic Dockyard is still in operation, run by the North Kent Industrial Locomotive Society.


title: Chatham, Kent

text: Buses are operated by Arriva Southern Counties and Nu-Venture to various destinations. They serve other towns in Medway including Gillingham, Grain, Strood and Rochester and also to other towns in Kent including Maidstone, Gravesend, Blue Bell Hill and Sittingbourne. There is also an express bus via Strood and Rochester and A2 to Bluewater in Greenhithe.


title: Chatham, Kent

text: In the 19th century the ecclesiastical parish of Chatham included Luton and Brompton and also Chatham Intra (land on the river that was administered by the City of Rochester).


title: Chatham, Kent

text: Chatham's parish church, St Marys, which stood on Dock Road, was rebuilt in 1788. St John's was a Waterloo church built in 1821 by Robert Smirke, and restructured in 1869 by Gordon Macdonald Hills; it ceased being an active church in 1964, and is currently used as an art project. St Paul's New Road was built in 1854; declared redundant in 1974, it has been demolished. St Peter's Troy Town was built in 1860. Christchurch Luton was built in 1843, replaced in 1884. The Royal Dockyard church (1806) was declared redundant in 1981.


title: Chatham, Kent

text: St Michael's is a Roman Catholic church, that was built in 1863. There is a Unitarian Chapel built in 1861.


title: Chatham, Kent

text: Chatham is reputed to be the home of the first Baptist chapel in north Kent, the Zion Baptist Chapel in Clover Street. The first known pastor was Edward Morecock who settled there in the 1660s. During Cromwell's time Morecock had been a sea-captain and had been injured in battle. His knowledge of the River Medway is reputed to have preserved him from persecution in the reign of King Charles II.


title: Chatham, Kent

text: Chatham Memorial Synagogue was built by Simon Magnus in 1867 on the Chatham end of Rochester High Street in Rochester.


title: Chatham, Kent

text: The town's Association Football club, Chatham Town F.C., plays in the Southern Counties East Football League, as do Lordswood F.C. The defunct Chatham Excelsior F.C. were one of the early pioneers of football in Southern England.


title: Chatham, Kent

text: Holcombe Hockey Club is one of the largest in the country, and are based in Chatham. The men's 1st XI are part of the England Hockey League.


title: Chatham, Kent

text: Kite Flying is possible, especially power kiting on the Great Lines Heritage Park (between Gillingham and Chatham) and at Capstone Farm Country Park.


title: Chatham, Kent

text: On a cultural level, Chatham gave birth to several movements in literature, art and music. In the period from 1977 until 1982 the Medway Delta Sound emerged. The term was coined as a joke by Chatham born writer painter and musician Billy Childish after Russ Wilkins' Medway based record label, Empire Records, used the phrase "From The Medway Delta". Several Medway Delta bands gained international recognition, including The Milkshakes, The Prisoners (see also James Taylor Quartet) and The Dentists.


title: Chatham, Kent

text: Out of the Kent Institute of Art & Design (KIAD), now the University for the Creative Arts (UCA) came the band known as Wang Chung. The vocalist and guitarist with Wang Chung, Jeremy Ryder, who is better known as Jack Hues attended KIAD. Alongside such individuals was Alan Denman, who became a well established lecturer at KIAD, and who founded The Flying Circuits in 1984, which became an urban theatre movement in the Medway Towns. Many students from KIAD played various acting roles within The Flying Circuits, in Chatham, Gillingham and London. The scenes that were performed by The Flying Circuits, were entirely based upon excerpts from the screenplay by Alan Denman, called the Electronic Town, that he wrote between January 1984 to October 1984, and which concerned a futuristic science fiction dystopia. Alan Denman also helped to form The Medway Poets with Billy Childish, Robert Earl, Bill Lewis, Sexton Ming and Charles Thomson. The Medway Poets used to meet regularly at the York Tavern & Railway Inn, in Ordnance Street, within Chatham, from 1974 to 1985, near to the Kent Institute of Art & Design (KIAD) at Fort Pitt in Rochester, and Chatham railway station. Chatham has always had a strong musical and creative arts heritage that has remained centred on local groups, many of whom were also part of the KIAD. Charles Thomson and Billy Childish went on to create the artistic movement known as Stuckism in 1999.


title: Chatham, Kent

text: There was a resurgence in the live music scene in early 2001, with an initial focus on the Tap 'n' Tin venue in Chatham. The essence of the original greatness of the Medway Delta Sound was revived by music and poetry evenings promoted by David Wise's Urban Fox Press, which also published several books by Medway poets and artists. In 2008. the independent arts organisation Medway Eyes was founded, specialising in music and photography. It had promoted several arts exhibitions and gigs at The Barge, that was located at 63 Layfield Road, in Gillingham (now closed) and The Nags Head at 292 High Street, in Rochester, but then in 2013 it disbanded.


title: Chatham, Kent

text: The Medway Poets were formed in 1977 and disbanded in 1982 having performed at the Kent Literature Festival and many others in South East England and on TV and Radio. They became a major influence to writers in the Medway Towns. From the core of this group the anti conceptual/pro painting movement of Remodernism came into being.


title: Chatham, Kent

text: Recent Medway artists of note include Kid Harpoon, Crybaby Special and The Monsters, Red Light, Underground Heroes, Tyrannosaurus Alan, Pete Molinari, Lupen Crook, Brigadier Ambrose, Stuart Turner and Theatre Royal.


title: Chatham, Kent

text: The term 'Chav', research suggests, does not derive from Chatham's name ("Chatham Average"), but is derived from the Romany word for 'youngster'. Before the Chatham Dockyard was closed down on the 31st March 1984, the cultural idea of the Chav did not actually exist in the Medway Towns.


title: Chatham, Kent

text: Local newspapers for Chatham include "Medway News" and "Medway Standard", both published by Kent Regional News and Media; and the "Medway Messenger", published by the KM Group. The town also has free newspapers in the "Medway Extra" (KM Group) and "yourmedway" (KOS Media).


title: Chatham, Kent

text: The local commercial radio station for Chatham is KMFM Medway, owned by the KM Group. Medway is also served by community radio station Radio Sunlightbased in Richmond road between the high street and the River Medway. The area can also receive the county wide stations BBC Radio Kent, Heart and Gold, as well as many radio stations in Essex and Greater London.


title: Chatham, Kent

text: Charles Dickens lived in the town as a boy, both in 'The Brook, Chatham' and in Ordnance Terrace before Chatham railway station was built just opposite. He subsequently described it as the happiest period of his childhood, and eventually returned to the area in adulthood when he bought a house in nearby Gad's Hill. Medway features in his novels. He then moved to Rochester, a nearby town, also part of the Medway Towns.


title: Common merganser

text: The common merganser (North American) or goosander (Eurasian) (Mergus merganser) is a large seaduck of rivers and lakes in forested areas of Europe, Asia, and North America. The common merganser eats mainly fish. It nests in holes in trees.


title: Common merganser

text: The first formal description of the common merganser was by Swedish naturalist Carl Linnaeus in 1758 in the 10th edition of his "Systema Naturae". He introduced the current binomial name "Mergus merganser". The genus name is a Latin word used by Pliny and other Roman authors to refer to an unspecified waterbird, and "merganser" is derived from "mergus" and "anser", Latin for "goose". In 1843 John James Audubon used the name "Buff-breasted Merganser" in addition to "goosander" in his book "The Birds of America".


title: Common merganser

text: It is long with a wingspan and a weight of ; males average slightly larger than females, but with some overlap. Like other species in the genus "Mergus", it has a crest of longer head feathers, but these usually lie smoothly rounded behind the head, not normally forming an erect crest. Adult males in breeding plumage are easily distinguished, the body white with a variable salmon-pink tinge, the head black with an iridescent green gloss, the rump and tail grey, and the wings largely white on the inner half, black on the outer half. Females and males in "eclipse" (non-breeding plumage, July to October) are largely grey, with a reddish-brown head, white chin, and white secondary feathers on the wing. Juveniles (both sexes) are similar to adult females but also show a short black-edged white stripe between the eye and bill. The bill and legs are red to brownish-red, brightest on adult males, dullest on juveniles.


title: Common merganser

text: Like the other mergansers, these piscivorous ducks have serrated edges to their bills to help them grip their prey, so they are often known as "sawbills". In addition to fish, they take a wide range of other aquatic prey, such as molluscs, crustaceans, worms, insect larvae, and amphibians; more rarely, small mammals and birds may be taken. As in other birds with the character, the salmon-pink tinge shown variably by males is probably diet-related, obtained from the carotenoid pigments present in some crustaceans and fish. When not diving for food, they are usually seen swimming on the water surface, or resting on rocks in midstream or hidden among riverbank vegetation, or (in winter) on the edge of floating ice.


title: Common merganser

text: In most places, the common merganser is as much a frequenter of salt water as fresh water. In larger streams and rivers, they float down with the stream for a few miles, and either fly back again or more commonly fish their way back, diving incessantly the whole way. In smaller streams, they are present in pairs or smaller groups, and they float down, twisting round and round in the rapids, or fishing vigorously in a deep pool near the foot of a waterfall or rapid. When floating leisurely, they position themselves in water similar to ducks, but they also swim deep in water like cormorants, especially when swimming upstream. They often sit on a rock in the middle of the water, similar to cormorants, often half-opening their wings to the sun. To rise from water, they flap along the surface for many yards. Once they are airborne, their flight is strong and rapid. They often fish in a group forming a semicircle and driving the fish into shallow water, where they are captured easily. Their ordinary voice is a low, harsh croak, but during the breeding season, males in display, as well as young, make a plaintive, soft whistle. Generally, they are wary, and one or more birds stay on sentry duty to warn the flock of approaching danger. When disturbed, they often disgorge food before moving. Though they move clumsily on land, they resort to running when pressed, assuming a very upright position similar to penguins, and falling and stumbling frequently.


title: Common merganser

text: Nesting is normally in a tree cavity, so it requires mature forest as its breeding habitat; they also readily use large nest boxes where provided, requiring an entrance hole in diameter. In places devoid of trees (like Central Asian mountains), they use holes in cliffs and steep, high banks, sometimes at considerable distances from the water. The female lays 6–17 (most often 8–12) white to yellowish eggs, and raises one brood in a season. The ducklings are taken by their mother in her bill to rivers or lakes immediately after hatching, where they feed on freshwater invertebrates and small fish fry, fledging when 60–70 days old. The young are sexually mature at the age of two years. Common mergansers are known to form crèches, with single females having been observed with over 70 ducklings at one time.


title: Common merganser

text: The species is a partial migrant, with birds moving away from areas where rivers and major lakes freeze in the winter, but resident where waters remain open. Eastern North American birds move south in small groups to the United States wherever ice-free conditions exist on lakes and rivers; on the milder Pacific coast, they are permanent residents. Scandinavian and Russian birds also migrate southwards, but western European birds, and a few in Japan, are largely resident. In some populations, the males also show distinct moult migration, leaving the breeding areas as soon as the young hatch to spend the summer (June to September) elsewhere. Notably, most of the western European male population migrates north to estuaries in Finnmark in northern Norway (principally Tanafjord) to moult, leaving the females to care for the ducklings. Much smaller numbers of males also use estuaries in eastern Scotland as a moulting area.


title: Common merganser

text: Overall, the species is not threatened, though illegal persecution by game-fishing interests is a problem in some areas. In February 2020, a rare common merganser sighting was documented in Central Park, New York; the bird was in obvious distress, with its beak being trapped by a piece of debris.


title: Common merganser

text: Within western Europe, a marked southward spread has occurred from Scandinavia in the breeding range since about 1850, colonising Scotland in 1871, England in 1941, and also a strong increase in the population in the Alps. They are very scarce in Ireland, with regular breeding confined to a few pairs in County Wicklow.


title: Common merganser

text: The goosander is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies.


title: Potsdamer Platz

text: Potsdamer Platz (, "Potsdam Square") is a public square and traffic intersection in the center of Berlin, Germany, lying about south of the Brandenburg Gate and the Reichstag (German Parliament Building), and close to the southeast corner of the Tiergarten park. It is named after the city of Potsdam, some to the south west, and marks the point where the old road from Potsdam passed through the city wall of Berlin at the Potsdam Gate. After developing within the space of little over a century from an intersection of rural thoroughfares into the most bustling traffic intersection in Europe, it was totally destroyed during World War II and then left desolate during the Cold War era when the Berlin Wall bisected its former location. Since German reunification, Potsdamer Platz has been the site of major redevelopment projects.


title: Potsdamer Platz

text: The history of Potsdamer Platz can be traced to 29 October 1685, when the Tolerance Edict of Potsdam was signed, whereby Frederick William, Elector of Brandenburg-Prussia from 1640 to 1688, allowed large numbers of religious refugees, including Jews from Austria and Huguenots expelled from France, to settle on his territory to repopulate it following the Thirty Years' War (1618–48). Several new districts were founded around the city's perimeter, just outside the old fortifications. The largest of these was Friedrichstadt, just south west of the historic core of Berlin, begun in 1688 and named after the new elector, Frederick William III, who became King Frederick I of Prussia. Its street layout followed the Baroque-style grid pattern much favoured at the time, and was based on two main axes: Friedrichstraße running north–south, and Leipziger Strasse running east–west. All the new suburbs were absorbed into Berlin around 1709–10. In 1721-3 a south-westwards expansion of Friedrichstadt was planned under the orders of King Frederick William I, and this was completed in 1732-4 by architect Philipp Gerlach (1679–1748). In this expansion, a new north–south axis emerged: Wilhelmstrasse.


title: Potsdamer Platz

text: In 1735–1737, after Friedrichstadt's expansion was complete, the Berlin Customs Wall was erected around the city's new perimeter. Potsdamer Platz would eventually develop around the gate at the west end of Leipziger Strasse, which turned south toward the hamlet of Schöneberg after leaving the city. This road, which had developed into part of a trading route running across Europe from Paris to St. Petersburg via Aachen, Berlin and Königsberg, became Elector Frederick William's route of choice to Potsdam, the location of his palace, in 1660. After Frederick II became king in 1740, the road was significantly improved, and became known as Potsdamer Straße; the gate became "Potsdamer Tor" (Potsdam Gate).


title: Potsdamer Platz

text: Just inside the gate was a large octagonal area, created at the time of Friedrichstadt's expansion in 1732-4 and bisected by Leipziger Strasse; this was one of several parade grounds for the thousands of soldiers garrisoned in Berlin at the height of the Kingdom of Prussia. Initially known as the "Achteck" (Octagon), on 15 September 1814 it was renamed Leipziger Platz after the site of Prussia's final decisive defeat of Napoleon Bonaparte at the Battle of Leipzig, which brought to an end the Wars of Liberation that had been going on since 1806. The gate itself was redesignated "Leipziger Tor" (Leipzig Gate) around the same time, but reverted to its old name a few years later.


title: Potsdamer Platz

text: Being outside Berlin, and therefore not subject to the same planning guidelines, Potsdamer Platz grew in a piecemeal and haphazard way, unlike Leipziger Platz, which had been planned and built all at once by Johann Philipp Gerlach. Prussian architect Friedrich David Gilly proposed a unified redesign of the two squares in 1797, but it was never built. In 1815, his pupil, Karl Friedrich Schinkel, proposed the area as the location for a National Memorial Cathedral, to be known as the "Residenzkirche", but this was never built either, due to lack of funds. However, Schinkel did get to rebuild the gate in 1823–1824, replacing what was little more than a gap in the customs wall with a much grander affair consisting of two matching Doric-style stone gate-houses, like little temples, facing each other across Leipziger Strasse. The one on the north side served as the customs house and excise collection point, while its southern counterpart was a military guardhouse, set up to prevent desertions of Prussian soldiers, which had become a major problem. The new gate was dedicated on 23 August 1824. Schinkel's proposal to add a garden was not implemented, but in 1828 a plan by gardener and landscape architect Peter Joseph Lenné went ahead. He redesigned the Tiergarten, a large wooded park formerly the Royal Hunting Grounds, gave his name to Lennéstraße, a thoroughfare forming part of the southern boundary of the park very close to Potsdamer Platz, and transformed a muddy ditch to the south into one of Berlin's busiest waterways, the Landwehrkanal.


title: Potsdamer Platz

text: Meanwhile, country peasantry were generally not welcome in the city, and so the gates also served to restrict access. However, the country folk were permitted to set up trading posts of their own just outside the gates, and the Potsdam Gate especially. It was hoped that this would encourage development of all the country lanes into proper roads; in turn it was hoped that these would emulate Parisian boulevards—broad, straight and magnificent, but the main intention was to enable troops to be moved quickly. Thus Potsdamer Platz was off and running.


title: Potsdamer Platz

text: It was not called that until 8 July 1831, but the area outside the Potsdam Gate began to develop in the early 19th century as a district of quiet villas, for as Berlin became even more congested, many of its richer citizens moved outside the customs wall and built spacious new homes around the trading post, along the newly developing boulevards, and around the southern edge of the Tiergarten. The development was piecemeal, but in 1828 this area just to the west of Potsdamer Platz, sandwiched between the Tiergarten and the north bank of the future Landwehrkanal, received royal approval for a more purposeful metamorphosis into a residential colony of the affluent, gradually filling with palatial houses and villas. These became the homes of civil servants, officers, bankers, artists and politicians among others, and earned the area the nickname "Millionaires' Quarter" although its official designation was "Friedrichvorstadt" (Friedrich's Suburb), or the "Tiergartenviertel" (Tiergarten Quarter).


title: Potsdamer Platz

text: Many of the properties in the neighborhood were the work of architect Georg Friedrich Heinrich Hitzig (1811–81), a pupil of Schinkel who also built the original "English Embassy" in Leipziger Platz, where the vast Wertheim department store would stand, although Friedrichvorstadt's focal point and most notable building was the work of another architect—and another pupil of Schinkel. The "Matthiaskirche" (St. Matthew's Church), built in 1844–6, was an Italian Romanesque-style building in alternating bands of red and yellow brick, and designed by Friedrich August Stüler (1800–65). This church, one of fewer than half a dozen surviving pre-World War II buildings in the entire area, forms the centrepiece of today's "Kulturforum" (Cultural Forum).


title: Potsdamer Platz

text: Meanwhile, many of the Huguenots fleeing religious persecution in France, and their descendants, had also been living around the trading post and cultivating local fields. Noticing that traffic queues often built up at the Potsdam Gate due to delays in making the customs checks, these people had begun to offer coffee, bread, cakes and confectionery from their homes or from roadside stalls to travelers passing through, thus beginning the tradition of providing food and drink around the future Potsdamer Platz. Larger and more purpose-built establishments began to take their place, and they in turn were superseded by bigger and grander ones. The former district of quiet villas was by now anything but quiet: Potsdamer Platz had taken on an existence all its own whose sheer pace of life rivalled anything within the city.


title: Potsdamer Platz

text: By the mid-1860s direct taxation had made the customs wall redundant, and so in 1866–7 most of it was demolished along with all the city gates except two – the Brandenburg Gate and the Potsdam Gate. The removal of the customs wall allowed its former route to be turned into yet another road running through Potsdamer Platz, thus increasing still further the amount of traffic passing through. This road, both north and south of the platz, was named Königgrätzer Straße after the Prussian victory over Austria at the Battle of Königgrätz on 3 July 1866, in the Austro-Prussian War.


title: Potsdamer Platz

text: The railway first came to Berlin in 1838, with the opening of the Potsdamer Bahnhof, terminus of a 26 km line linking the city with Potsdam, opened throughout by 29 October (in 1848 the line would be extended to Magdeburg and beyond). Since the city authorities would not allow the new line to breach the customs wall, still standing at the time, it had to stop just short, at Potsdamer Platz, but it was this that kick-started the real transformation of the area, into the bustling focal point that Potsdamer Platz became.


title: Potsdamer Platz

text: Three years later a second railway terminus opened. Six hundred meters to the southeast, with a front facade facing Askanischer Platz, the Anhalter Bahnhof was the Berlin terminus of a line running as far as Jüterbog and extended to Dessau, Kothen and beyond.


title: Potsdamer Platz

text: Both termini began life modestly, but to cope with increasing demand, both went on to much bigger and better things, a new Potsdamer Bahnhof, destined to be Berlin's busiest station, opening on 30 August 1872 and a new Anhalter Bahnhof, destined to be the city's biggest and finest, on 15 June 1880. This latter station benefitted from the closure of a short-lived third terminus in the area – the Dresdner Bahnhof, located south of the Landwehrkanal, which lasted from 17 June 1875 until 15 October 1882.


title: Potsdamer Platz

text: A railway line once ran through Potsdamer Platz: a connecting line opened in October 1851 and running around the city just inside the customs wall, crossing numerous streets and squares at street level, and whose purpose was to allow goods to be transported between the various Berlin stations, thus creating a hated traffic obstruction that lasted for twenty years. Half a dozen or more times a day, Potsdamer Platz ground to a halt while a train of 60 to 100 wagons trundled through at walking pace preceded by a railway official ringing a bell. The construction of the Ringbahn around the city's perimeter, linked to all the major stations, allowed the connecting line to be scrapped in 1871, although the Ringbahn itself was not complete and open for all traffic until 15 November 1877.


title: Potsdamer Platz

text: Potsdamer Platz was served by both of Berlin's two local rail systems. The U-Bahn arrived first, from the south; begun on 10 September 1896, it opened on 18 February 1902, with a new and better sited station being provided on 29 September 1907, and the line itself being extended north and east on 1 October 1908. In 1939 the S-Bahn followed, its North-South Link between Unter den Linden and Yorckstraße opening in stages during the year, the Potsdamer Platz S-Bahn station itself opening on 15 April.


title: Potsdamer Platz

text: By the second half of the 19th century, Berlin had been growing at a tremendous rate for some time, but its growth accelerated even faster after the city became the capital of the new German Empire on 18 January 1871. Potsdamer Platz and neighbouring Leipziger Platz came into their own afterward. Now firmly in the centre of a metropolis whose population eventually reached 4.4 million, making it the third largest city in the world after London and New York, the area was ready to take on its most celebrated role. Vast hotels and department stores, hundreds of smaller shops, theatres, dance-halls, cafés, restaurants, bars, beer palaces, wine-houses and clubs, all started to appear. Some of these places became internationally known.


title: Potsdamer Platz

text: Also, a very large government presence, with many German imperial departments, Prussian state authorities and their various sub-departments, came into the area, taking over 26 former palaces and aristocratic mansions in Leipziger Platz, Leipziger Strasse and Wilhelmstraße. Even the Reichstag itself, the German Parliament, occupied the former home of the family of composer Felix Mendelssohn (1809–47) in Leipziger Strasse before moving in 1894 to the vast new edifice near the Brandenburg Gate, erected by Paul Wallot (1841–1912). Next door, the Herrenhaus, or Prussian House of Lords (the Upper House of the Prussian State Parliament), occupied a former porcelain factory for a while, before moving to an impressive new building erected on the site of the former Mendelssohn family home in 1899–1904 by Friedrich Schulze Colditz (1843–1912). This building backed on to an equally grand edifice in the next street (Prinz-Albrecht-Straße), also by Colditz, that had been built for the Preußischer Landtag (the Prussian Lower House), in 1892–9.


title: Potsdamer Platz

text: Potsdamer Platz was also the location of Germany's first electric street lights, installed in 1882 by the electrical giant Siemens, founded and based in the city.


title: Potsdamer Platz

text: The heyday of Potsdamer Platz was in the 1920s and 1930s. By this time it had developed into the busiest traffic center in all of Europe, and the heart of Berlin's nightlife. It had acquired an iconic status, on a par with Piccadilly Circus in London or Times Square in New York. It was a key location that helped to symbolize Berlin; it was known worldwide, and a legend grew up around it. It represented the geographical center of the city, the meeting place of five of its busiest streets in a star-shaped intersection deemed the transport hub of the entire continent. These were:


title: Potsdamer Platz

text: As well as the stations and other facilities and attractions already mentioned, in the immediate area was one of the world's biggest and most luxurious department stores: Wertheim. Founded by German merchant Georg Wertheim (1857–1939), designed by architect Alfred Messel (1853–1909), opened in 1897 and extended several times over the following 40 years, it ultimately possessed a floor area double that of the Reichstag, a 330-metre-long granite and plate glass facade along Leipziger Strasse, 83 elevators, three escalators, 1,000 telephones, 10,000 lamps, five kilometers of pneumatic tubing for moving items from the various departments to the packing area, and a separate entrance directly from the nearby U-Bahn station. It also contained a summer garden, winter garden and roof garden, an enormous restaurant and several smaller eating areas, its own laundry, a theater and concert booking office, its own bank, whose strongrooms were underground at the eastern end of the building, and a large fleet of private delivery vehicles. In the run-up to Christmas Wertheim was transformed into a fairytale kingdom, and was well known to children from all over Germany and far beyond.


title: Potsdamer Platz

text: In Stresemannstrasse, and paralleling the Potsdamer Bahnhof on its eastern side, was another great magnet for shoppers and tourists alike – a huge multi-national-themed eating establishment: the Haus Vaterland. Designed by architect Franz Heinrich Schwechten (1841–1924), who was also responsible for the Anhalter Bahnhof and the Kaiser Wilhelm Memorial Church, it was erected in 1911–12 as the Haus Potsdam. 93 m in length and with a dome rising 35 m above the pavement at the north (Stresemannstrasse) end, it contained the world's largest restaurant – the 2,500-seat Café Piccadilly, plus a 1,200-seat theatre and numerous offices. These included (from 1917 to 1927), the headquarters of Universum Film AG (aka UFA or Ufa), Germany's biggest film company.


title: Potsdamer Platz

text: On 16 August 1914, less than three weeks after the start of World War I, the Café Piccadilly was given a new name – the more patriotic-sounding Café Vaterland. However, in 1927–8 the architect and entrepreneur Carl Stahl-Urach (1879–1933) transformed the whole building into a gastronomic fantasy land, financed and further elaborated upon by new owners the Kempinski organisation. It reopened on 31 August 1928 as the Haus Vaterland, offering "The World in One House," and could now hold up to 8,000 guests at a time. The Café Vaterland had remained largely untouched, but the 1,200-seat theatre was now a 1,400-seat cinema. The rest of the building had been turned into a large number of theme restaurants, all served from a central kitchen containing the largest gas-fueled cooking plant in Europe. These included: Rheinterrasse, Löwenbräu (Bavarian beer restaurant), Grinzing (Viennese café and wine bar), Bodega (Spanish winery), Csarda (Hungarian), Wild West Bar (aka the Arizona Bar) (American), Osteria (Italian), Kombüse (Bremen drinking den – literally "galley"), Rübchen (Teltow, named after the well-known turnip dish "Teltower Rübchen", made with turnips grown locally in the small town of Teltow just outside Berlin), plus a Turkish café and Japanese tearoom; additionally there was a large ballroom. Up to eight orchestras and dance bands regularly performed in different parts of the building, plus a host of singers, dancers and other entertainers. It should be pointed out here though that not all of these attractions existed simultaneously, owing to changes in those countries that Germany was or was not allied to, in the volatile years leading up to and during World War II, a good example being the closure of the Wild West Bar following America's entry into the war as an enemy of Germany.


title: Potsdamer Platz

text: Among the major hotels at or near Potsdamer Platz were two designed by the same architect, Otto Rehnig (1864–1925), and opened in the same year, 1908. One was the 600-room Hotel Esplanade (sometimes known as the "Grand Hotel Esplanade"), in Bellevuestrasse. Charlie Chaplin and Greta Garbo were guests there, and Kaiser Wilhelm II himself held regular "gentlemen's evenings" and other functions there in a room that came to be named after him – the Kaisersaal.


title: Potsdamer Platz

text: The other was the Hotel Excelsior, also 600 rooms but superior provision of other facilities made it the largest hotel in Continental Europe, located in Stresemannstrasse opposite the Anhalter Bahnhof and connected to it by a 100-metre-long subterranean passageway complete with a parade of underground shops.


title: Potsdamer Platz

text: Two other hotels which shared the same architect, in this case Ludwig Heim (1844–1917), were the 68-room Hotel Bellevue (sometimes known as the "Grand Hotel Bellevue"), built 1887–8, and the 110-room Palast Hotel, built 1892–3 on the site of an earlier hotel. These stood on either side of the northern exit from Potsdamer Platz along Ebertstraße. The Bellevue was well known for its Winter Garden.


title: Potsdamer Platz

text: Meanwhile, facing the Palast Hotel across the entrance to Leipziger Platz (the Potsdam Gate), was the 400-room Hotel Fürstenhof, by Richard Bielenberg (1871–1929) and Josef Moser (1872–1963), erected in 1906–1907, also on the site of an earlier building. With its 200-metre-long main facade along Stresemannstrasse, the Fürstenhof was less opulent than some of the other hotels mentioned, despite its size, but was still popular with business people. The new U-Bahn station was being built at the same time as the hotel and actually ran through the hotel's basement, cutting it in half, thus making the construction of both into something of a technical challenge, but unlike the Wertheim department store (and contrary to several sources), the hotel did not enjoy a separate entrance directly from the station.


title: Potsdamer Platz

text: The Weinhaus Huth, with its distinctive corner cupola, was a wedge-shaped structure located in the angle between Potsdamer Strasse and Linkstrasse (literally "Left Street"), and with entrances in both streets. Wine merchant Friedrich Karl Christian Huth, whose great-grandfather had been "kellermeister" (cellar-master) to King Friedrich II back in 1769, had founded the firm in 1871 and taken over the former building in Potsdamer Straße on 23 March 1877. His son, the wine wholesale dealer William ("Willy") Huth (1877–1967), took over the business in 1904 and, a few years later, commissioned the replacement of the building by a new one on the same site. Running right through the block into Linkstrasse, this new Weinhaus Huth was designed by the architects Conrad Heidenreich (1873–1937) and Paul Michel (1877–1938), and opened on 2 October 1912, and contained a wine restaurant on the ground floor, and wine storage space above, so it had to take a lot of weight. It was thus given a strong steel skeleton, which would stand the building in very good stead some three decades after its completion. Famous for its fine claret, numerous members of European society were made welcome there as guests. A total of 15 chefs were employed there, and Alois Hitler Jr., the stepbrother of the future Nazi dictator Adolf Hitler, was a waiter there in the 1920s, before he opened his own restaurant and hotel at Wittenbergplatz, in the western part of the city.


title: Potsdamer Platz

text: Café Josty was one of two rival cafés (the other being the "Astoria", later "Café Eins A"), occupying the broad corner between Potsdamer Strasse and Bellevuestrasse. The Josty company had been founded in 1793 by two Swiss brothers, Johann and Daniel Josty, who had emigrated to Berlin from Sils in Switzerland and set up a bakery from which the café was a 1796 offshoot. It had occupied various locations including (from 1812 till 1880), a site in front of the Berlin City Palace, before moving to Potsdamer Platz in the latter year. A major player on the Berlin café scene, Josty attracted writers, artists, politicians and international society: it was one of "the" places to be seen. The writer Theodor Fontane, painter Adolph von Menzel, and Dadaist Kurt Schwitters were all guests; Karl Liebknecht, the Spartacus Communist movement leader read a lot here and even made some key political speeches from the pavement terrace, while author Erich Kästner wrote part of his 1929 bestseller for children, "Emil und die Detektive" (Emil and the Detectives), on the same terrace and made the café the setting for an important scene in the book.


title: Potsdamer Platz

text: Despite the prestige associated with its name, Café Josty closed in 1930. It then went through an odyssey of re-openings, closures and relaunches under a number of different names including "Conditorei Friediger", "Café Wiener", "Engelhardt Brau" and "Kaffee Potsdamer Platz" (sometimes appearing to have two or more names simultaneously), before its eventual destruction in World War II.


title: Potsdamer Platz

text: Among the many beer palaces around Potsdamer Platz were two in particular which contained an extensive range of rooms and halls covering a large area. The Alt-Bayern in Potsdamer Strasse was erected by architect Wilhelm Walther (1857–1917) and opened in 1904. After closing in 1914, it underwent a revamp before reopening in 1926 under the new name Bayernhof.


title: Potsdamer Platz

text: Meanwhile, in Bellevuestrasse, sandwiched between Café Josty and the Hotel Esplanade but extending right through the block with a separate entrance in Potsdamer Strasse, was the Weinhaus Rheingold, built by Bruno Schmitz (1858–1916) and opened on 6 February 1907. Intended to be a concert venue until concerns were raised about increased traffic problems in the already congested streets, it was ruled that it should serve a gastronomic purpose only. Altogether it could accommodate 4,000 guests at a time, 1,100 of these in its main hall alone. Many of the total of 14 banquet and beer halls had a Wagnerian theme – indeed, the very name of the complex was taken from the Wagner opera "Das Rheingold", the first of the four parts of the cycle Der Ring des Nibelungen, although this name did hark back to the building's planned former role as a concert venue. Another building by the same architect but which still stands – the "Rosengarten" in Mannheim, has a remarkably similar main facade.


title: Potsdamer Platz

text: Finally, on the corner between Potsdamer Strasse and the Potsdamer Bahnhof, stood Bierhaus Siechen, built by Johann Emil Schaudt (1874–1957), opened in 1910 and relaunched under a new name, Pschorr-Haus.


title: Potsdamer Platz

text: At 8.00 p.m. on 29 October 1923, Germany's first radio broadcast was made from a building (Vox-Haus) close by in Potsdamer Strasse. Standing alongside the Weinhaus Rheingold's Potsdamer Strasse entrance, this five-storey steel-framed edifice had been erected as an office building in 1907-8 by architect and one-time Berlin inspector of buildings Otto Stahn (1859–1930), who was also responsible for the city's Oberbaumbrücke over the River Spree. In 1920 the Vox-group had taken over the building and the following year commissioned its remodelling by Swiss architect Rudolf Otto Salvisberg (1882–1940), and then erected two transmitting antennae. Despite several upgrades between December 1923 and July 1924, the nearby Hotel Esplanade's formidable bulk prevented the transmitter from functioning effectively and so in December 1924 it was superseded by a better sited new one, but Vox-Haus lived on as the home of Germany's first radio station, Radiostunde Berlin, founded in 1923, renamed Funkstunde in March 1924, but it moved to a new home in 1931 and closed in 1934.


title: Potsdamer Platz

text: In addition, the former Millionaires' Quarter just to the west of Potsdamer Platz had become a much favoured location for other countries to site their embassies. By the early 1930s there were so many diplomats living and working in the area that it came to be redesignated the "Diplomatic Quarter". By 1938, 37 out of 52 embassies and legations in Berlin, and 28 out of 29 consulates, were situated here.


title: Potsdamer Platz

text: The first traffic light tower in Germany was erected at Potsdamer Platz on 20 October 1924 and went into service on 15. December 1924 in an attempt to control the sheer volume of traffic passing through.


title: Potsdamer Platz

text: This traffic had grown to extraordinary levels. Even in 1900, more than 100,000 people, 20,000 cars, horse-drawn vehicles and handcarts, plus many thousands of bicycles, passed through the platz daily. By the 1920s the number of cars had soared to 60,000. The trams added greatly to this. The first four lines had appeared in 1880, rising to 13 by 1897, all horse-drawn, but after electrification between 1898 and 1902 the number of lines had soared to 35 by 1908 and ultimately reached 40, carrying between them 600 trams every hour, day and night. Services were run by a large number of companies.


title: Potsdamer Platz

text: After 1918 most of the tram companies joined. In 1923, at the peak of the Hyperinflation the tram traffic was stopped for two days and a new communal company called "Berliner Straßenbahn-Betriebs-GmbH" was founded. Finally in 1929 all communal traffic companies (Underground, Tram and Buses) were unified into the "Berliner Verkehrsbetriebe" (Berlin Transport Services) company.


title: Potsdamer Platz

text: At the Potsdamer Platz up to 11 policemen at a time had tried to control all this traffic but with varying success. The delays in tram traffic increased and the job was very dangerous for the policemen. The "Berliner Straßenbahn-Betriebs-GmbH" started researches to control the traffic on the main streets and places in 1924. Berlin traffic experts visited colleagues in Paris, London and New York. They had to organize the traffic, define traffic rules and select a solution to control the traffic. In New York, Fifth Avenue they found traffic light towers designed by Joseph H. Freedlander in 1922 which can be regarded as a model for the Berlin tower.


title: Potsdamer Platz

text: The Potsdamer Platz five-sided 8.5 m high traffic tower was designed by Jean Kramer, a German architect. The traffic lights were delivered by Siemens & Halske and mounted on top of the tower cabin. A solitary policeman sat in a small cabin at the top of the tower and switched the lights around manually, until they were automated in 1926. Yet some officers still remained on the ground in case people did not pay any attention to the lights. The tower remained until October 1937, when it was removed to allow for excavations for the new S-Bahn underground line. On 26 September 1997, a replica of the tower was erected, just for show, close to its original location by Siemens, to celebrate the company's 150th anniversary. The replica was moved again on 29 September 2000, to the place where it stands today.


title: Potsdamer Platz

text: The traffic problems that had blighted Potsdamer Platz for decades continued to be a big headache, despite the new lights, and these led to a strong desire to solve them once and for all. By now Berlin was a major centre of innovation in many different fields including architecture. In addition, the city's colossal pace of change (compared by some to that of Chicago), had caused its chief planner, Martin Wagner (1885–1957), to foresee the entire centre being made over totally as often as every 25 years. These factors combined to produce some far more radical and futuristic plans for Potsdamer Platz in the late 1920s and early 1930s, especially around 1928–9, when the creative fervour was at its peak. On the cards was an almost total redevelopment of the area. One design submitted by Wagner himself comprised an array of gleaming new buildings arranged around a vast multi-level system of fly-overs and underpasses, with a huge glass-roofed circular car-park in the middle. Unfortunately the worldwide Great Depression of the time, triggered by the Wall Street Crash of 1929, meant that most of the plans remained on the drawing board. However, in Germany this depression was virtually a continuation of an economic morass that had blighted the country since the end of World War I, partly the result of the war reparations the country had been made to pay, and this morass had brought about the closure and demolition of the Grand Hotel Belle Vue, on the corner of Bellevuestrasse and Königgrätzer Strasse, thus enabling one revolutionary new building to struggle through to reality despite considerable financial odds.


title: Potsdamer Platz

text: Columbushaus was the result of a plan by the French retail company Galeries Lafayette, whose flagship store was the legendary Galeries Lafayette in Paris, to open a counterpart in Berlin, on the Grand Hotel Belle Vue's former site, but financial worries made them pull out. Undaunted, the architect, Erich Mendelsohn (1887–1953), erected vast advertising boards around the perimeter of the site, and the revenue generated by these enabled him to proceed with the development anyway. Columbushaus was a ten-storey ultra-modern office building, years ahead of its time, containing Germany's first artificial ventilation system, and whose elegance and clean lines won it much praise. However, despite a Woolworths store on its ground floor, a major travel company housed on the floor above, and a restaurant offering fine views over the city from the top floor, the economic situation of the time meant that it would not be followed by more buildings in that vein: no further redevelopment in the immediate vicinity of Potsdamer Platz occurred prior to World War II, and so Columbushaus would always seem out of place in that location. Nevertheless, its exact position showed that the platz was starting to be opened out: the former hotel had mostly stood on a large flagged area laid out in front of it, indicating that the new building curved away from the existing street line; this would have enabled future street widening to take place.


title: Potsdamer Platz

text: Columbushaus was completed and opened in January 1933, the same month that the Nazi dictator Adolf Hitler (1889–1945) came to power. Hitler had big plans for Berlin, to transform it into the "Welthauptstadt" (World Capital) Germania, to be realised by his architect friend Albert Speer (1905–81). Under these plans the immediate vicinity of Potsdamer Platz would have got off fairly lightly, although the Potsdamer Bahnhof (and the Anhalter Bahnhof a short distance away) would have lost their function. The new North-South Axis, the linchpin of the scheme, would have severed their approach tracks, leaving both termini stranded on the wrong side of it. All trains arriving in Berlin would have run into either of two vast new stations located on the Ringbahn to the north and south of the centre respectively, to be known as "Nordbahnhof" (North Station) and "Südbahnhof" (South Station), located at Wedding and Südkreuz. In Speer's plan the former Anhalter Bahnhof was earmarked to become a public swimming pool; the intended fate of the Potsdamer Bahnhof has not been documented.


title: Potsdamer Platz

text: Meanwhile, the North-South Axis would have cut a giant swathe passing just to the west of Potsdamer Platz, some 5 km long and up to 100 m wide, and lined with Nazi government edifices on a gargantuan scale. The eastern half of the former Millionaires' Quarter, including Stüler's Matthiaskirche, would have been totally eradicated. New U-Bahn and S-Bahn lines were planned to run directly beneath almost the whole length of the axis, and the city's entire underground network reoriented to gravitate towards this new hub (at least one tunnel section, around 220 metres in length, was actually constructed and still exists today, buried some 20 metres beneath the Tiergarten, despite having never seen a train). This was in addition to the S-Bahn North-South Link beneath Potsdamer Platz itself, which went forward to completion, opening in stages in 1939. In the event, a substantial amount of demolition did take place in Potsdamer Straße, between the platz itself and the Landwehrkanal, and this became the location of the one Germania building that actually went forward to a state of virtual completion: architect Theodor Dierksmeier's "Haus des Fremdenverkehrs" (House of Tourism), basically a giant state-run travel agency. More significantly, its curving eastern facade marked the beginnings of the "Runden Platz" (Round Platz), a huge circular public space at the point where the North-South Axis and Potsdamer Straße intersected. Additionally, the southern edge of the Tiergarten was to be redefined, with a new road planned to slice through the built-up area immediately to the north of Columbushaus (although Columbushaus itself would remain unscathed); this road would line up with Voßstraße, one block to the north of Leipziger Platz. Here Albert Speer erected Hitler's enormous new Reichskanzlei building, and yet even this was little more than a dry run for an even larger structure some distance further away.