Bourne Gorges

Beyond Villard-de-Lans D531 runs down into the Bourne valley, which narrows into the Gorges de la Bourne, a tremendous rocky defile in which the road is carried through tunnels and over bridges. Between Choranche and Pont-en-Royans two interesting caves can be reached from the road, the Grotte du Bournillon and the Grottes de la Choranche (in which is an underground lake).