Envisaged by its designer, Claude-Nicolas Ledoux, as the ‘ideal city’, the 18th-century Saline Royale in Arc-et-Senans, 35km southwest of Besançon, is a showpiece of early Industrial Age town planning. Although his urban dream was never fully realised, Ledoux’s semicircular Royal Saltworks has been a Unesco World Heritage Site since 1982.
