Minecraft wiki entry for Shelters, associated text: Create a base floating in the sky with no bridges or stairs connecting it to land. Of course, it doesn't have to be this way to build it! The no-connections idea can be accomplished with waterfalls, piston elevators, and nether portals. Add other sky islands nearby with bridges to connect them, and it'll be like you never left the ground! If you truly don't want any connections to land, even with the waterfalls and nether portals and elevators, gather up all the resources you'll need and seal yourself away in the sky. (But make sure you have a bed up there in case you die.) For extra entertainment, make a smaller island and plunge it into darkness, and watch mobs walk right off. To make it even more entertaining, place some arrow dispensers hooked up to pressure plates on the island, and even make signs all along the edge.