Minecraft wiki entry for Shelters, associated text: Make this room by digging a 6×6×6 hole and building the base pyramid out of your selected material (Iron is cheapest unless you have a Trading Hall, but you can also use Netherite, Diamonds, Emeralds and Gold). Also, you could put in a few chests with diamonds, Netherite, iron, emeralds and gold and/or make it look like an altar.