The Wieliczka Salt Mine () is a salt mine in the town of Wieliczka, near Kraków in southern Poland. From Neolithic times, sodium chloride (table salt) was produced there from the upwelling brine. The Wieliczka salt mine, excavated from the 13th century, produced table salt continuously until 2007, as one of the world's oldest operating salt mines. Throughout its history, the royal salt mine was operated by the Żupy Krakowskie (Kraków Salt Mines) company. Due to falling salt prices and mine flooding, commercial salt mining was discontinued in 1996. The Wieliczka Salt Mine is now an official Polish Historic Monument (Pomnik Historii) and a UNESCO World Heritage Site. Its attractions include the shafts and labyrinthine passageways, displays of historic salt-mining technology, an underground lake, four chapels and numerous statues carved by miners out of the rock salt, and more recent sculptures by contemporary artists. History The Wieliczka Salt Mine reaches a depth of , and extends via horizontal passages and chambers for over 287 kilometres (178 miles). The rock salt is naturally of varying shades of grey, resembling unpolished granite rather than the white crystalline substance that might be expected. Since the 13th century, brine welling up to the surface had been collected and processed for its sodium chloride (table-salt) content. In this period, wells began to be sunk, and the first shafts to be dug to extract the rock salt. From the late 13th to the early 14th century, the Saltworks Castle was built. Wieliczka is now home to the Kraków Saltworks Museum. King Casimir III the Great (reigned 13331370) contributed greatly to the development of the Wieliczka Salt Mine, granting it many privileges and taking the miners under his care. In 1363 he founded a hospital near the salt mine. It is said that he turned a Poland of wood into a Poland of stone due to the great amount of wood from the neighbouring forests used as scaffolding and supports. Over the period of the mine's operation, many chambers were dug and various technologies were added, such as the Hungarian horse treadmill and the Saxon treadmill for hauling salt to the surface. During World War II, the mine was used by the occupying Germans as an underground facility for war-related manufacturing. The mine features an underground lake, exhibits on the history of salt mining, and a 3.5-kilometre (2.2-mile) visitors' route (less than 2 percent of the mine