Close to downtown Birmingham, the Sloss Furnaces are the only blast furnaces in the nation that are fully (and officially) open to the public. Visitors are permitted to wander all over on their own, even into crawl spaces and up old stairways. Public events are held there, such as concerts, and demonstrations of iron production. Every Halloween the site is turned into a creepy haunted house. The iron works dates back to 1881, was modernized in the 1930s, and shut down in 1971. The last owner donated it to the state of Alabama for historical preservation. The state donated it to the city of Birmingham, and it became a preserved historic site open to the public in 1983. Though some of the plant was removed, two blast furnaces dating back to 1931, and a compressor building from 1902, remain, with their contents and appurtenances.