Hundred year-old mills buried 23m deep?  Guaranteed: you can only see them at the Col-des-Roches in Le Locle Valley! These mills are proof of man's ingenuity in energy production, and they are in line with the unique hydraulic history of the Neuchâtel mountains. Le Locle Valley was actually formed at the end of the Cretaceous Period - 130 million years ago - after the Jura mountains folded. The Bied, a water body that made its way to open-air, rushed down into the earth and created a cave. The « Cul-des-Roches » - re-baptised « Col-des-Roches » in the 19th century for some discreet reason - turned into an « emposieu,» a natural well that links water sources on the surface to those underground.

So the setting was laid out for the extraordinary industrial history that was to start in 1660. In order to benefit from the « drain », the area where the water disappeared underground, the well-to-do miller Jonas Sandoz dug a cave there and built an underground mill. He put up five hydraulic wheels to grind grain and prepare linen.  This incredible adventure took a toll on his fortune, however, and the milling entrepreneur soon had to sell the mills to his creditors. After several owners, Le Locle Commune ended up buying the set-up in 1884, with the intention of managing the Bied waters.

The site quickly turned into a big garbage dump and a «promo»  slaughterhouse for the animals that didn't make it across the border. Le Locle sewers were also emptied here.  A century later, in 1973, a fraternity of a few Le Locle millers decided to save the site. After 37,000 hours of work and almost as many wheelbarrows of dug-out waste, the site was opened to the public. Since 1987 a cave and museum have been created, recounting the incredible epic of these mills. And there's even rumour that they might function again one day....

Contact and information: www.lesmoulins.ch

Fondation des Moulins souterrains du Col-des-Roches
Col 23, CH-2400 Le Locle
Ph. +41 (0)32 931 89 89
Practical Information (access, timings): click here
Fondation des Moulins souterrains du Col-des-Roches