Underground vaults are secure storage spaces located beneath the surface of the earth. Crypts, hypogeums, and catacombs are all types of underground vaults. A CRYPT is a small chamber or vault beneath the floor of a church or other building, typically used as a burial place. A hypogeum is an underground structure, usually associated with ancient civilizations, that was used for religious or ceremonial purposes. Catacombs are underground cemeteries, often associated with ancient Rome, consisting of galleries with recesses for tombs.