This is Gringotts Bank. That is where the Sorcerer's Stone is in volt 713. The things who work there are called Goblins. The money is called Galleons, Sickles, and Knuts. There are 17 Sickles in a Galleon, and 29 Knuts in a Sickle, meaning there are 493 Knuts in a Galleon. Around the edge of each coin is a series of numerals which represent a serial number belonging to the Goblin that cast the coin.