Vault 52 is an abandoned vault in Rapid City, South Dakota. Its experiment was to test out a new type of pill that would make the vault dwellers work harder, stay awake longer, and eat less. This worked well enough until 2258 when the Vault's pill supply ran out, and the inhabitants went through severe withdrawal symptoms, such as paranoia, hysteria, and psychosis, causing them to leave and ravage Rapid City. After that, Vault 52 was occupied a few other times by other groups, most recently a group of cannibals known as the Carnists who use the Vault as bait.