From the 8th century to 1962, the Great Saltwork of Salins-les-Bains has used the evaporation of natural salty waters to make salt. This salty water came from a former sea, which covered the Jura 210 millions years ago. The salt remaining after the evaporation of this sea became a rock, called rock salt, lying today at 246 meters depth. The rainwater infiltrating the ground becomes salty by dissolving the rock salt. Then, thanks to a natural pressure phenomenon, it rises up on the surface to give birth to salty springs.
The salt, called the "white gold", was obtained by heating this salty water using at first wood and then coal (form the 19th century).
The salt production lasted for 1200 years and made Salins-les-Bains very powerful and rich throughout the Middle-Ages. Half of the Franche-Comté's income came from this city, which was the second largest town of the region.
In 1775, the Royal Saltwork of Arc-et-Senans was built by the architect Claude Nicolas Ledoux, nearby the Chaux Forest (3rd largest hardwood forest in France) to increase the local salt production. Since it hadn't any salt or salty water, the salty water from Salins-les-Bains went to Arc-et-Senans through wooden pipes. It was called a "saumoduc" and was 21 kilometers long, which is the distance between the two cities. Since it was not profitable enough, the saltwork of Arc-et-Senans was closed in 1895.
In 1962, the Saltwork of Salins-les-Bains was closed, after 1200 years of production. Indeed, the Saline was not profitable anymore and quite archaic. The evolution of the food preservation technics and the competition with mines and salt marshes made it collapse.
Since 1966, the Great Saltwork is owned by the city of Salins-les-Bains.
Its history, its pumping system still functionning and its incredible underground architecture make of the Great Saltwork of Salins-les-Bains an unique site in Europe and one of the jewels of the Franche-Comté's heritage.
The Saltwork of Salins-les-Bains has played a crucial part in the history of the city and its region. This is why it got several national and international recognitions.
In 1971, the Great Saltwork obtained its first recognition with the inscription of the underground gallery to the Historical Monuments. It became one of the first industrial site recognized in France.
The Great Saltwork of Salins-les-Bains was registered on the 27th of June 2009 on the Unesco World Heritage list, in extension of the Royal Saltwork of Arc-et-Senans (registered in 1982). You can access the webpage of both saltworks on the Unesco website by clicking here : http://whc.unesco.org/fr/list/203.
Since the 8th of December 2009, all the buildings belonging to the Great Saltwork of Salins-les-Bains have been listed as Historical Monument for consistency reasons.