Cathedral is a major location in Fallout. To the outside world, the cathedral is nothing more then an innocent set up for the Children of the Cathedral organization, which tries to bring love and peace to the wastes. Below it, however, lies a secret underground Vault (more specifically, the Los Angeles Vault), which serves as a home and base for the Master. The Los Angeles Vault was a demonstration Vault built by Vault-Tec to advertise its series of fallout shelters. As such, it was not part of the Vault Experiment and was never assigned a number. When the Great War started, many people took shelter in this Vault, and eventually emerged in 2092, founding the Boneyard.