The Wieliczka Salt Mine is located close to Kraków in Poland. The world oldest salt mine is still in operation. Now-a-days there are many tours given trough the mine. After walking 378 steps downwards a wooden staircase the tour starts at 64 metres underground. After walking 3 kilometres in the salt mine you’d be 135 metres underground. (Don’t worry, there’s an elevator which brings you back above the ground).

Copyright: Jeffrey Tork