Several hundred meters below the streets of the town Wieliczka snakes a real wonder of mankind: The Wieliczka Salt Mine, where miners since the 13th century have dug out more than 280 km of tunnels. Today the salt mine is UNESCO enlisted (along with Bochnia Salt Mine) and one of the biggest tourist sights in Poland. The tours will take you down 389 wooden steps (135 m), through damp tunnels all carved out of pure grey rock salt – and yes, you're welcome to check the taste for yourself by licking walls. There are artworks carved out of the rock salt by the miners through time, but the main attraction is the underground cathedral, also carved out of solid salt, with a highly polished salt floor, salt crystal chandeliers and a salt relief of the last supper. If salt is to your liking, you can even get married here.