The Moulins souterrains du Col-des-Roches near Le Locle (NE) are a fascinating piece of industrial heritage: A guided tour takes you around 23 metres down into a limestone grotto, where water power was once used to operate mills and even a sawmill.

This ingenious facility was created in the 17th century because the Bied stream had too little gradient in the valley floor – so people harnessed the waterfall plunging into the cave. Today, you can see the restored mechanisms in the tunnels and grottoes and gain a vivid impression of how ingeniously natural forces were used here.

Upstairs, a small museum area complements the visit and explains the function and significance of the facilities.
Individual visitors can use audio guides (in several languages), and depending on the season there are also public guided tours.
The excursion is perfect for a rainy day or summer outing, as it is pleasantly cool underground and the atmosphere feels truly “mystical”.