I'm interested in compiling a list of bookstores around the world that stock a good selection of high-level mathematical books. The aim is so that a mathematician travelling, or on holiday, can easily check the list to see if there is a book store nearby that she or he could happily spend an hour browsing in.

Some particulars:

• It must be a physical bookstore.
• It should have a good selection of research level books. This criterion is designed to exclude stores that stock primarily popular books and undergraduate textbooks, such as some university bookshops.