The mine produced enormous wealth for Poland. But it also become a cultural treasure trove, filled with natural wonders like underground lakes and elaborate salt carvings.
The mine's caverns have been used to host royalty and world leaders as well as a world record attempt in underground ballooning.
Visitors can travel almost 450 feet down and wander through a portion of the mine's 152 miles of passageways.
Wieliczka Salt Mine is about 10 miles outside of Krakow, one of Poland's most historic cities. The building that houses the mine entrance is pretty modest compared to what's underground.
At a depth of 330 feet, one of the most impressive rooms you reach is St Kinga's chapel, complete with chandeliers and devotional carvings into the salt walls.
After descending a grand staircase, you arrive in a vast hall lined with wall carvings and an altar to St Kinga at one end.
St Kinga's chapel even features a version of Leonardo da Vinci's "Last Supper" carved into a solid rock salt wall.
Here's a close-up of one of the salt chandeliers.
This salt-carved scene shows St Kinga. Legend says she asked for her wedding dowry in salt and miraculously made the mine appear at Wieliczka. Here, she is on the left, being presented with a lump of rock salt.
