Vault
A vault is a structure used to store prison and exile-pearls and other valuables. A vault, in it's most basic form, is typically an obsidian pyramid, as this is the hardest structure to destroy. To protect this pyramid, other fortifications may be built around it, such as rings of obsidian walls, cobwebs and bastions, sometimes referred to as "nerd rings". A bunker or tower is often constructed above the vault, where supplies for fighters are stored. A large, ringed vault is often referred to as a "megavault".
History
Vaults have existed since Civcraft 1.0 after prisonpearl was added. The more advanced "megavaults" were pioneered by the nation of FAGT in Civcraft 2.0. Such advanced vaults were thought to be unbreakable until the fall of Nox towards the end of 2.0.