Minecraft wiki entry for Building_a_metropolis, associated text: Floating: Make a city on the water, preferably on the middle of an ocean or lake, as there is most space for this city type. The houses could be boats or rafts, and the main building could be a big flagship. The city can be also built on a large platform on the top layer of water, so it looks like it is floating. For transportation, you could build connected nether portals in the city, and the mainland. Boats and Frost Walker boots are also a good form of transportation in this city type. The city might also be built inside a single, giant ship. If you choose to make only one giant ship, you might fill it with animals of all kinds, to make it resemble Noah's Ark.