WIELICZKA SALT MINE, POLAND
Beneath the town of Wieliczka lies another town that was built mostly by miners who used to work in a salt mine. Wieliczka is one of the world’s oldest salt mines and it produced salt from the 13th century when it was opened until 2007. During all those years, miners turned it not just into an underground town, but into a work of art, since they carved tens of statues as well as four chapels entirely out of the rock salt. The most interesting tourist attraction is the Underground Salt Cathedral with all its details made from salt, like the crystals on the chandeliers. It was placed on the UNESCO’s World Heritage Sites list in 1978 and thousands of people visit it every year. If that doesn’t sound interesting enough, there is also a huge underground lake that you could visit.