Saint Kinga legend, Wieliczka Salt Mine. Salt sculptures of Princess Kinga (1224-1292, left) being presented with her engagement ring (centre) in a block of salt mined from the earth at the location where the Wieliczka Salt Mine was founded. Princess Kinga of Hungary married Boleslaw V of Poland, and part of her dowry was salt for Poland, leading to the legend shown here. The salt mine at Wieliczka, Poland, is one of the oldest in the world, and is still in use in the 21st century. By the 19th century, vast underground caverns had been excavated to depths of several hundred metres. In 1978, the mine became a UNESCO World Heritage Site.