Visit the Turda Salt Mine

Underground cathedral carved into the tunnels of a working salt mine.

Snorkel over WWII bulldozers and trucks the US Army dumped into the sea.

Sunken Byzantine reservoir under Istanbul, its columns rising from black water.

Descend into Salina Turda, a former salt mine in Transylvania turned underground theme park. Explore the vast Rudolf Mine chamber (about 42m deep) with its illuminated salt walls, take a boat ride on the underground lake in the Terezia Mine, and see the wooden walkways and a Ferris wheel set inside the mine. The constant cool air and towering salt formations make it one of Romania's most surreal attractions.

Ride one of the world's longest trains.

Jagged coral pinnacles of the interior.

Explore the historic silver mine in Tarnowskie Gory, a UNESCO World Heritage site with underground tunnels and mining history

Visit the Krzemionki prehistoric flint mines in Poland, a UNESCO World Heritage site showcasing ancient mining techniques and Neolithic history