These wondrously symmetrical early–Industrial Age saltworks were designed to be an 'ideal city' by Claude-Nicolas Ledoux. Though Ledoux's plans never came to fruition, the 18th-century saltworks and its outbuildings were listed by Unesco in 1982 for their visionary composition and are renowned in France as an architectural masterwork. They now house displays dedicated to the design concept, Ledoux's life, and the history of salt.
Three-star accommodation is available on site.
Through modern eyes, this masterpiece of industrial design has a sinister side: radiating out from a central columned hall, its semi-circular shape ensured no worker could escape their supervisor's eyes for even a moment.
Arc-et-Senans is 35km southwest of Besançon, on route D17.