Muzeum Żup Krakowskich Wieliczka

You visit inside a disused section of one of the world's oldest rock salt mines. The underground exhibition lies 135 m down and shows salt mining and boiling in historic workings, like an open-air mining museum below ground. On the surface stands the medieval Żupny Castle, seat of the salt works administration from the late 13th century. The mine has been on the UNESCO list since 1978.