Dungeons are found throughout all Biomes and occur at various layers in the ground.
Dungeons vary in degrees of size, difficulty, and complexity. From simple, basic dungeons with only a few protectors to large, complex dungeons, containing many protectors and require the use of various Switch controlled Mechanical Doors.
To raid a dungeon you must destroy all protectors. Once the last protector is removed, a notification will alert you on screen and text will appear in the chat window.