Salt Mine in Wieliczka

It's the oldest operational salt mine in Europe which has been working for over 700 years. Since 1978, the mine is on UNESCO's list of World Class Landmarks of Cultural and Natural Heritage - where it was listed among the top 12 attractions in the world. The tourist route open to sightseers is only a small part of the entire mine.
The mine includes 7.5 million square meters of post-excavation space on nine levels, each between 64 and 327 meters. The tourist route extends to level three only - to the depth of 135 meters. During the 2,5 hour tour, you will travel underground approximately 3.5 km. During this time you will see 30 of the more than 2148 chambers.