Bethesda SoftworksFor those unfamiliar with the franchise (where have you been?!), the Fallout games are set after a Great War, in which the world was devastated by nuclear blasts. In anticipation of this, the US government contracted the Vault-Tec corporation to create huge underground shelters, in order to protect as many citizens as possible. Because only 122 vaults were built, a lottery system took place in order to decide who was given the privilege of becoming a vault dweller. However, unbeknownst to the majority of the inhabitants, the vaults weren't just created to protect their dwellers from nuclear war. Many of them were part of a project named the "Societal Preservation Program", in which the vaults and their populaces were subjected to extensive, often depraved, experiments. The vaults were initially designed to allow the government to study various subdivisions of the American populace, in order to observe how best to re-colonise the planet. However, the more extreme experiments were commissioned by the Enclave, a secret organisation that wished to inherit the planet themselves. The horrific experiments that took place in many of the vaults were intended to help the Enclave prepare for the dangers of a post-apocalyptic world. This list takes a look at the vaults from the Fallout universe with the creepiest backstories, from the bizarre, immoral experiments, to unexpected disasters that sealed the fate of the inhabitants forever.