While traveling throughout southern Poland I went to this salt mine where everything you see is carved out of the salt rock. It is simply gorgeous. Wieliczka Salt Mine, located in the town of Wieliczka in southern Poland. The mine was built in the 13th century and produced table salt continuously until 2007. It was one of the world's oldest salt mines still in operation and reaches a depth of 1,073 ft and is over 178 miles long.