This steep, V-shaped valley runs north for 149km all the way from the pretty little town of St-Sauveur-sur-Tinée (elevation 490m) to the Vallée de l'Ubaye. En route, it climbs up and over the Col de Restefond la Bonette, Europe's highest road pass – and invariably the last one to open after the spring thaw (usually in late May but sometimes as late as early June). It's a favourite for road-trippers and motorbikers, and occasionally features on the Tour de France. During winter, the valley can only be accessed from the south.
At 1100m elevation, the sky-top village of Roure is also worth a detour thanks to its amazing alpine arboretum – as long as you can handle the hair-raisingly steep, twisty mountain road. From the 1920s until 1961, villagers used a 1850m-long cable to transport items up the mountain; the cable still remains.