Minecraft wiki entry for Defeating_a_monument, associated text: Once inside, it can be advantageous to set up a base of operations. Doors or slime blocks can be used to seal any entrances to a chosen room, and sponge blocks can be used to quickly clear it of water. Then you might move in resources such as furnaces for drying sponges, chests to hold potions and other supplies, a bed in case you die, a nether portal for easier access via the Nether, and a cow for milk refills.