Royal Saltworks at Arc-et-Senans

Near the Forest of Chaux in Franche-Comté, Claude-Nicolas Ledoux built one of the strangest and most visionary industrial buildings of the eighteenth century. The Royal Saltworks at Arc-et-Senans was approved by an edict of Louis XV in 1773 and built between 1775 and 1779 to boil brine into salt, then a precious state monopoly. The brine did not come from here: it flowed through a pipeline 21 kilometres long from the springs of Salins-les-Bains, so that it could be boiled down with firewood from the nearby forest. At its peak the works produced some 40,000 quintals of salt a year.

Ledoux's first design, in 1774, arranged the buildings around a square linked by colonnades with 144 Doric columns; the king found it too grand, and the architect produced instead the plan that makes the site unforgettable: a great semicircle. Along its curve stand the workers' lodgings and workshops; on the diameter stand the two long salt-boiling halls, each 80 metres long, and between them, at the centre of the whole composition, the Director's House, from which everything could be watched. The architecture speaks the language of its purpose: the entrance pavilion opens through a heavy portico into an artificial grotto of rough-hewn rock, and throughout the site stone urns carved on the walls appear to spill petrified brine, as if the salt water itself had been turned into ornament.

The saltworks were meant as only the first piece of an ideal city, a complete circular town of Chaux that Ledoux imagined around them and set out in his drawings. It was never built, but the idea turned this factory into a founding text of utopian architecture and urban planning. Production itself lasted a little over a century: competition from sea salt and complaints about pollution brought it to an end in 1895, and in 1918 a lightning strike destroyed the chapel in the Director's House.

Listed as a UNESCO World Heritage Site in 1982, the saltworks were joined in 2009 by the Great Saltworks of Salins-les-Bains, the source of their brine. Today the site is a cultural centre: the Director's House and the halls hold exhibitions, a museum shows models of Ledoux's buildings and projects, and themed gardens fill the space inside the semicircle, the stage each year for a gardens festival.

Getting there

The saltworks are in the village of Arc-et-Senans, about 23 km from Dole. Arc-et-Senans station, on the regional TER network, is about 100 metres from the entrance. The nearest airport is Dole-Jura (DLE) at Tavaux, about 27 km away.