Bochnia Salt Mine

The Bochnia Salt Mine () in Bochnia, Poland, is one of the oldest salt mines in the world and is the oldest commercial company in Poland. The Bochnia salt mine was established between the 12th and 13th centuries after salt had been discovered there, and became part of the royal mining company, "żupy krakowskie" (Kraków Salt Works). In 1990 the mine ceased producing salt but remains a tourist attraction.
In 1981 the Bochnia salt mine was declared a heritage monument. It is one of Poland's official national Historic Monuments ("Pomnik historii"), as designated on 6 October 2000, and is overseen by the National Heritage Board of Poland.
The chapel in the mine has train tracks running through it.
History.
The mine shafts measure in length at about 330–468 metres in depth below the surface, at 16 levels.
In 2013 the mine was added to the UNESCO World Heritage List as an extension of the Wieliczka Salt Mine inscription of 1978.
August Passage.
The August Passage is the main communication and transportation route in the mine. It runs from the east to the west of mine, connecting in a straight line the bottom ends of the Campi and Sutoris shafts. It is at a depth of 176m from the top of the Sutoris shaft and 212m counting from the top of the Campi shaft. The August Passage was initially called the Long Stove (Piec Długi). Its first part, extending between the Rabsztyn Chute and a Campi Shaft, was built in the years 1723-1743, in accordance with a design by Jan Gottfried Borlach. His great achievements was to regulate routes in the mine by ensuring their straightening and leveling. As a result of this, over the next decades, the August Passage was able to reach a length of nearly .
Excavated chambers, shafts and passages form an underground town, which is open to sightseers. The largest of the preserved chambers has been converted into a sanatorium.
Ważyn Chamber.
The Ważyn Chamber was named after the name of the administrator (podżupek) Andrzej Ważyński. The deepness of this chamber, the biggest in Bochnia Salt Mine, is 248m; its length is 255m; its maximum width is 14.4m; and maximum height is 7.2m. The chamber uses no supporting pillars. Salt from Ważyn chamber was extracted from 1697 until the 1950s. For the purposes of creating a sanatorium these old pits were expanded with a loading-hauling-dumping (LHD) unit machine. These works took place until 1984. Thanks to them the Ernest Chute from the 17th century impressively presents itself on the stripped chamber's roof.
The Ważyn chamber has a specific microclimate, with a constant temperature between , high humidity (about 70%) and favourable ionisation of the air saturated by sodium chloride and valuable microelements, like magnesium, manganese and calcium. The air in the chamber distinguishes itself by its purity. The chamber is equipped with beds: up to 300 people can sleep here. The other parts of Ważyn Chamber are fields for playing volleyball, basketball and handball, restaurant, and conference facilities.