Fallout 4 review The true nature of Fallout's vaults is one of the worst-kept secrets of Bethesda's wartorn universe. These vast underground networks of metallic tunnels were ostensibly built by the US government to protect people from the nuclear fallout, and while they technically do this, their main purpose is to serve as giant testing labs on how humans respond to various environmental conditions. The official number of vaults in existence is 122, with only a handful of them being run without an ulterior experimental motive in mind. Each vault was led by an Overseer, whose job it was to report back to the government (or latter the Enclave organisation) about the progress of the experiments. The experiments ranged from the slightly kooky to the heinous. Vault 12 from the original Fallout, for example, never had its doors sealed, so the effects of radiation on people could be studied. It makes Fallout 3's Vault 101 look pretty tame by comparison - where keep people were to live and breed in the Vault for an undisclosed period of time, making it perfect for studying the effects of inbreeding. Yep, Vault-Tec and the government are vile in Fallout 4, and true to the series' tradition, Fallout 4 also has its fair share of vaults and accompanying horror stories. Here they all are in full catastrophic detail. This list reveals the vaults' locations and backstories, but nothing about quests or events that occur throughout Fallout 4.