Partway down Diagon Alley, near its intersection with Knockturn Alley, stands an imposing snow-white marble building: Gringotts Wizarding Bank . "Towering over the other shops" , it is the place where British witches and wizards store their money and other valuables, in vaults miles below ground. The vaults are heavily guarded - as Hagrid says.
The centuries-old bank is run by goblins, and they alone know the secrets of the twisting underground passages and the enchantments (and creatures!) in place to defend against intruders.. The goblins have a code that forbids them to speak of the bank's secrets, and would consider it "base treachery" to break any part of that code
