Minecraft wiki entry for Building_a_metropolis, associated text: Upside-Down: Forget logic! Make your city upside down! Make a giant ceiling, then construct the buildings literally from top to bottom. Have all decorations, such as chairs, tables, or TVs upside down. As for the roads, you can use over-hanging bridges to connect the buildings, or you can use a Railway system. If you can fit creatures inside your upside down houses you can rename them with a "Dinnerbone" name-tag and they will be upside down! Use the flip shader for help. Careful- it's crazy upside-down!