De Wallen, also known as Walletjes, is the largest and best-known red-light district in Amsterdam, a major tourist attraction. It is located in the heart of the oldest part of Amsterdam, covering several blocks south of the church Oude Kerk and crossed by several canals. De Wallen is a network of alleys containing several hundred tiny one-room apartments rented by female prostitutes (and some ladyboys) who offer their services from behind a window or glass door, typically illuminated with red lights. The area also has a number of sex shops, sex theatres, peep shows, a sex museum, a cannabis museum, and a number of coffee shops that sell marijuana. De Wallen, together with the prostitution areas Singelgebied and Ruysdaelkade, form the Rosse Buurt (red light areas) of Amsterdam.