The Salina Turda, located in Transylvania is not a building but a highly unique location! This 2,000-year-old site was formerly a salt mine and was used as such from antiquity until 1932. In recent years it has become home to a museum, Ferris wheel, spa, bowling alley, miniature golf course, and even contains a lake which visitors can explore with paddle boats. All of these attractions are located a mere 368 feet underground!
In 2004 Business Insider ranked the Salina Turda as #1 on its top 10 list of “Coolest Underground Places.” As of 2012, an estimated 2 million tourists have visited it.