The association Les Phosphatières du Quercy decided at the end of the 1980s to save the phosphate mines from oblivion by developing the Cloup d'Aural in Bach. Converted into a tourist site, these former phosphate mines opened their doors in early summer 2000. It received more than 2,000 visitors from the start. The route deploys from the surface and the hot climate of the Causses, to the bottom of the chasm of more than 98 feet (30 m). It ends at the heart of the freshness and surprisingly lush vegetation of the phosphate mines.