One of the most vertiginous roads of the Vercors, first crosses through the huge Lente forest, before going over Machine pass. This daring route is carved into the impressive limestone rock face, overhanging the Cholet valley, 600m/1,968ft below. After passing through several tunnels the road comes out above Royans, unfolding to reveal grandiose scenery around Laval coombe. Experienced motorists only!