Places
Gringotts
Gringotts is the wizarding bank in Diagon Alley, run by goblins. Vaults sit deep under London, some behind dragons and waterfall charms. Harry’s trust vault is there, and the Philosopher’s Stone is briefly in a high-security vault. In the last book the trio breaks into the Lestrange vault for Helga Hufflepuff’s cup.

First mention
Harry Potter and the Philosopher's StoneChapter: Diagon Alley
Hagrid takes Harry inside to collect money for his school list, and they also remove a small package from another vault.