Minecraft wiki entry for The_Void, associated text: The Void is an empty biome that generates only a 33×33 Void Start Platform centered on a block of cobblestone at coordinates 8, 3, 8. No mobs (passive or hostile) apart from phantoms can spawn without spawn eggs, spawners or commands. In The Void superflat preset, since the world is made up of one layer of air, only the platform generates. Below the platform, there is just void.