The Cavern layer is the largest layer of the world, beginning just below the Underground and extending down until the Underworld layer. Darker stone background tiles characterize it. Stone is the predominant block in this layer (as opposed to Dirt in the Underground). Caverns contain occasional Underground Cabins where valuables can be found, as well as Glowing Mushroom biomes, mini-biomes like the Spider Cave, and occasional traps. In the lower areas of the Cavern layer, pools of lava can be found.
Furthermore, the Cavern layer contains the underground versions of several surface biomes: the Ice biome, Underground Jungle, Underground Desert, and Underground Corruption/Crimson and Hallow. A large section of the Dungeon also extends through the Cavern layer.
- Spawns from Mother Slimes
NPC happiness 
|Underground / Cavern / The Underworld|
For more information, see NPC happiness.
This content is transcluded from Biome backgrounds § Cavern.
- Desktop 188.8.131.52:
- Desktop 1.3.2: Geysers now spawn as traps.
- Desktop 184.108.40.206:
- Desktop 1.2.2: New "Alternate Underground" soundtrack.
- Desktop 1.1: Random traps added.
- Desktop-Release: Introduced.
- Console-Release: Introduced.
- Switch 1.0.711.6: Introduced.
- Mobile-Release: Introduced.
- 3DS-Release: Introduced.