Minecraft wiki entry for Building_a_metropolis, associated text: Forest: Build your city in a forest, but rather than cutting the trees down, build your city on top of them, construct some hollow giant trees with logs, bark, stripped logs and stripped bark blocks and build inside them, and make buildings to hang from the trees or wrap around them. You can connect the trees with wooden bridges. This city can be quite easy to hide, if you use blocks that look like wood or leaves. For added stealth have your citizens wear brown or green leather armor or use brown or green skins. If you want to defend this city, construct hideouts in the trees for archers. Using lava or fire is heavily discouraged, as almost everything in this city is flammable. The best place to build this is the jungle biome, due to the abundance of trees there, but any kind of forest works.