The Unfinished Vault (named Fake Vault 13 in-game) is a small cave with some construction signs for what was to be a Vault constructed by the Vault-Tec Corporation.
Prior to the Great War, this cave was the construction site of what was to become a Vault. The location of the cave can be learned from a holodisk that can be bought from Merk in the New California Republic for $1000.[1]
Layout[]
The layout of the cave is identical to that of Vault 13. Upon entering, there is a long tunnel that breaks off into two directions: east to one room, and north to another room and some construction signs.
↑The Chosen One: "{196}{}{I'm looking for Vault 13.}" Merk: "{205}{}{Just so happens, I've got a map to Vault 13. It's only 1000 bucks. You interested?}" (Scmerk.msg)