Originating in Germany, the Danube flows southeast for 2,860 km (1,780 mi), passing through or touching the border of Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before emptying into the Black Sea.
The Danube is one of the world’s greatest rivers. It is the second longest river in Europe after the Volga and the longest river in the European Union. It measures 2,857 km in length and up to 1.5 km in width, with depths between 1 to 8 metres and drains 817,000 km². The Sava is shared by Slovenia, Croatia, Bosnia and Herzegovina, Serbia and Montenegro. The Siret flows from its source in Ukraine into Romania. The Siret River Basin is the third-largest catchment area of any Danube tributary, and is situated to the east of the Carpathians. The Danube rises in Germany's Black Forest and flows through the heartland of Austria, first forming the border of Austria and Slovakia, and then Slovakia and Hungary. Leaving Hungary, it runs through Croatia and Serbia to form the boundary between Serbia and Romania and then the Romania and Bulgaria border. The Danube is not only Europe's second longest river—more than twice the length of the Rhine and nearly three and a half times the length of the Rhone—rhône but it flows through ten different countries and more than a dozen languages are spoken on its. banks Originating in Germany, the Danube flows southeast for 2,860 km (1,780 mi), passing through or touching the border of Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before emptying into the Black Sea. Its drainage basin extends into nine more nations. The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania and by river ships to Kelheim, Bavaria, Germany; smaller craft can navigate further upstream to Ulm, Wuerttemberg, Württemberg. Germany about 60 of its tributaries are also. navigable The name Danube is applied from the confluence of the two source rivers Brigach and Breg near Donaueschingen in the Black Forest. The source of the Danube is sometimes considered to be a spring in the castle of Donaueschingen.  The Danube (/ˈdaenjuːb/ ˈDæNJUːB-dan, ewb also known by other) names Is 'europe s-second longest, river After volga, river and also the longest river in The European union, region located In central And Eastern. europe The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania and by river ships to Kelheim, Bavaria, Germany; smaller craft can navigate further upstream to Ulm, Wuerttemberg, Württemberg. Germany about 60 of its tributaries are also. navigable What I find fascinating is that the Danube River used to be the longest river in Europe before the fall of the Iron Curtain in 1989. Since then, the longest river is Volga, with the length of 3,692 kilometres (2,294 miles). When you consider the river Breg as the source, the Danube is 2,888 kilometers (1,794 miles) long. When compared to all the rivers, the Danube is only the 40th longest river in the world.  River Severn | River Thames. The River Nile is the longest river in the world. It measures 6,695 kilometres from its source in Burundi, along the White Nile, to its delta on the Mediterranean Sea. Officially, the shortesr river is the D River, Oregan, USA, which is just 37 metres long. The biggest river in the world, measured by the amount of water that flows down it, is the Amazon. Closed to tourists for many years, the exotic lower reaches of the River Danube once again welcome visitors. With an overall length of over 1800 miles, the River Danube flows from its source in the Black Forest of Germany through eight countries to the Black Sea. Explore east of Budapest through Eastern Europe and the Iron Gate to the Danube Delta and the Black Sea. 
http://www.danubeparks.org/?story=9 http://www.avalonwaterways.com/Europe-Rivers/Danube/ https://en.wikipedia.org/wiki/Danube http://www.answers.com/Q/Where_is_the_source_of_the_Danube_river https://en.wikipedia.org/wiki/Danube http://danube-river.com/danube-river http://resources.woodlands-junior.kent.sch.uk/homework/rivers/longest.htm http://www.cruisingholidays.co.uk/river/danube-blacksea/
Where is the river Danube and where is its source and length