Vault 15

A manhole there will lead you to the entrance of the vault, inhabited by animal vermin by now, and later in Fallout 2 inhabited by human vermin.

Vault 15 is one of the Vaults built by Vault-Tec. Like Vault 13, for example, it was part of a social experiment. It was supposed to remain closed for fifty years, was overcrowded, and contained occupants of extremely diverse ideologies and cultures.

History

The dark and rusty entrance of Vault 15, with its door exploded from the interior.

The situation in Vault 15 led to a schism, and all the inhabitants splitted in four groups. The Jackals, the Vipers and the Khans turned into raiders that only wanted to kill everyone in the wasteland ; while the fourth group founded the Shady Sands, that would later become the great and powerful city of NCR.

In FOnline: 2238

Vault 15 in FOnline: 2238 uses its carnation from the original Fallout rather than Fallout 2's excavated, cliff-side, raider-overrun version. Thus it is not very interesting and there's nothing to do there except kill rats and explore what's left of it.