Gringotts Wizarding Bank is the only known bank of the wizarding world and it is operated primarily by goblins. A snowy white building, near the intersection of Knockturn Alley and Diagon Alley, Gringotts towers over all neighbouring shops. Customers pass through a set of bronze doors and then silver ones before entering the lobby. The main floor is paved with marble and has a long counter stretching along its length, behind which goblin clerks work at tasks such as counting coins and updating account ledgers. Within, wizards and witches keep their money and other valuables in vaults that are protected by very complex and very strong security measures. The vaults extend for miles under London and are accessible through rough stone passageways navigated by magic carts that travel speedily along their tracks. Gringotts also offers Muggle-Wizarding currency exchange.