Underground



The Underground is the first layer below the surface. It starts at a depth of 0ft and can be recognized by its background which contain many small rocks. Unlike Dirt Walls this background stop players from hammering holes for daylight and building wood platforms at any place (if they don't join onto a nearby block). The music changes when the player goes a few feet deeper past the intersection of the rocky and rockless walls.

The Underground is home to more aggressive enemies than the surface, as well as more treasure. Worlds generated after 1.1 patch have here traps, which you have to watch out for.

At hardmode the Underground may be converted by the Hallow or Corruption, but it will not create Underground Hallow/Corruption biomes and monsters mostly will be the mix of surface Hallow/Corruption and regular Underground enemies.

If a player continues downwards, eventually they will reach the Cavern layer.