Torna and Citadeles street corner holds an entrance to the branch of Central Bank of Latvia - Money World. It is open for public, but you need to apply for the visit in advance. Here is a virtual tour and more info on "where and how to".
The Bank of Latvia is located on the "edge" of Old Riga and right at the end of Vansu bridge. It is one block building, so it is surrounded by four streets and has an inner yard. If you would like to see, what kind of money can be found in there, click on the post title.