Fallout: what's your favourite Vault?

The Fallout universe has quite a lot of interesting things about it. Let's talk about a huge project called Vaults. Some Vaults didn't have anything wrong with them, they were simply put, the survival shelters they were made out to be. However, the majority of all known Vaults had some sick experiments about them. So, from Vault 1-114, what's your favourite Vault and why? Mine is Vault 11 because of its sick experiments.