Bochnia Royal Salt Mines (Poland) is an extension to the Polish Wieliczka Salt Mine, inscribed on the World Heritage List in 1978, which is now to be known as the Wieliczka and Bochnia Royal Salt Mines. The Wieliczka Saltworks Castle used for the management of the property was also added to the site. The rock salt deposit in Wieliczka-Bochnia has been mined since the 13th century and is the oldest of its type in Europe. Spread over several levels, it has 300 km of galleries with underground chapels, storerooms and more. It includes altars and statues sculpted in the salt, making a fascinating pilgrimage into the past of a major industrial undertaking that developed over 700 years.