Since the start of the 20th century Stockport has moved away from being a town dependent on cotton and its allied industries to one with a varied base. It makes the most of its varied heritage attractions, including a national museum of hatting, a unique system of Second World War air raid tunnel shelters in the town centre, and a late medieval merchants' house on the 700-year-old Market Place. In 1967, the Stockport air disaster occurred, when a British Midland Airways C-4 Argonaut aeroplane crashed in the Hopes Carr area of the town, resulting in 72 deaths among the passengers and crew.