Minecraft wiki entry for Beginner%27s_guide, associated text: The walls and ceiling of a shelter can be made entirely out of material the player has gathered, but it is usually faster to dig your shelter out of a hill, or to close off the openings of a nearby cave. When doing this, you need to avoid the few blocks affected by gravity, which for now are just sand and gravel. A player may already have a hole dug out from gathering cobblestone earlier in the day, which can be quickly fitted out as as a shelter. Sometimes, there may be a naturally generated structure nearby that would serve as a shelter. If you're stuck on an open plain, you may yet need to build a small hut out of dirt, planks, and/or stone.