ALBAWABA - Just steps southeast of Krakow, Poland, after descending 380 steps into the earth, a door opens onto a mysterious world, the Wieliczka Salt Mine.
The Wieliczka Salt Mine is not merely an archaeological site, but an entire city carved from salt. It was designated a UNESCO World Heritage Site in 1978, having operated for nearly seven centuries before commercial production ceased in 1996.
Along more than 150 miles of hand-carved tunnels, the miners left behind a breathtaking engineering legacy that continues to attract up to 9,000 visitors daily, according to CNN.
For her part, tour guide Patricia Antoniac explains that the gray color of the walls is due to natural impurities, as the rock is composed of up to 95% sodium chloride, while other minerals and deposits give it its distinctive color.
