Minecraft wiki entry for Building_a_metropolis, associated text: Cloud City: Build your city in the sky. Use snow or wool for buildings and use glass for streets. You can build the ground out of white blocks to look like clouds, and maybe even actually build it at cloud level. It is possible to make "rain clouds" by hiding water inside artificial clouds made, for example, from wool. This will cause dripping water to appear on the bottom of the cloud.You could also put real water under the clouds, or make the rain out of blocks like individual glass panes. Another idea is to make lightings from the clouds, or a rainbow. There are different ideas you can apply.