Dear DeeDee, David is right that that two Green Vaults are at the Dryden Palace (Residenzschloss). You didn't ask about the Porcelain Collection, but--as David says--it's in a nearby but separate facility, the Zwinger. There is a Combi-Ticket for 21 Euros that will let you into the Historic Green Vault and the rest of the Residenzschloss, including the New Green Vault. (Separate tickets would be 12 Euros each.) Because you need advance tickets to the Historic Green Vault, I assume you need advance tickets for the Combi-Ticket as well. The New Green Vault is filled with treasures, and hassle-free. The Historic Green Vault is filled with treasures, but is not hassle-free. However, the Historic Green Vault is more impressive, because the treasures are displayed in incredible rooms with rich decorations. So, the Historic Green Vault itself is an attraction, in addition to its contents. Each of the Vaults requires a half-day to be enjoyed, in my opinion. So, if you have a full day it would be worthwhile to see them both. If you have a half-day, I would pick one or the other, depending on my preference. Both are definitely worth seeing. If you are at a hotel, the concierge should be able to get you advanced tickets for the Historic Green Vault, or Combi-Tickets. If are not in a situation with a concierge, use the numbers or e-mail address that David provided. There is a website, but for some reason it can't be posted in the answer. NOTE THAT THE ENTIRE RESIDENZSCHLOSS IS CLOSED ON TUESDAYS. If you are constrained to a Tuesday, you will miss both Green Vaults, although you can see the Old Masters Art Gallery and the Porcelain Collection in the Zwinger/Semper complex. (They are open on Tuesdays, but closed on Mondays.) Both Green Vaults are worth a special trip, so don't give up! Sincerely, Herman from Buffalo