Fallout Online: Australia is a Project that basically places the "Fallout" Style world inside Australia. With Zombies, Crafting, Slavery, Children, Building Houses and Farms! You can do just about ANYTHING!
This can be only opened and closed from the inside by anyone.
Nothing can get into the vault from the inside. and since Vaults may be crafted by players. I think many players will make there new home a nice underground vault