Vault 76

Vault 76 is one of the Vault-Tec vaults shown on the computer in the Citadel. The Vault-Tec Terminal in the Citadel lists Vault 76 as a "control" vault, with 500 occupants. The vault was designed to open after 20 years. It was among the seventeen total control vaults, meaning it functioned precisely according to occupants' expectations.

Appearances
Despite being mentioned in Fallout 3, Vault 76 does not appear in the game.But In the Pc Version The G.E.C.K (Witch you can Download) alllows you to make it and on the G.E.C.K website is the turtorial is how to make a Vault And Vault 76 Happens to be the The turtorial since its not in the game in the first place.