Chamber Underground is a term used to describe three different types of underground spaces: Caverns, Crypts, and Catacombs. Caverns are large, naturally occurring underground spaces, often with stalactites and stalagmites. Crypts are usually man-made underground chambers, often used as burial sites. Catacombs are also man-made underground chambers, but they are typically used for religious purposes. All three of these underground spaces can be referred to as Chamber Underground.