The Royal Saltworks of Arc-et-Senans ( https://www.salineroyale.com/home/ ) are located in France and are included on the UNESCO world heritage list since 1982.
They have been designed by french utopist architect Claude-Nicolas Ledoux ( https://en.wikipedia.org/wiki/Claude_Nicolas_Ledoux ) during the 18-th century.
Ledoux aimed to build a perfect city around the saltworks activity ( http://socks-studio.com/2016/11/09/the-ideal-city-of-chaux-by-claude-nicolas-ledoux-1773-1806/ )
but only half of the circular saltworks have been built.
My MOC is a microscale version of the present saltworks :
Royal Saltworks of Arc-et-Senans by Daniel Stoeffler, on Flickr
Royal Saltworks of Arc-et-Senans by Daniel Stoeffler, on Flickr
Royal Saltworks of Arc-et-Senans by Daniel Stoeffler, on Flickr
Enjoy and have also a look to my microscale version of Neuf-Brisach :