A long narrowing valley of great historical significance. The gap at Exilles is overlooked by the fort where Dumas’s Man in the Iron Mask was once a reluctant guest. The area is mainly of interest to skiers, hill-climbers and walkers. Sauze d’Oulx is the Italian resort most favoured by the British. A longer walk, but a gentle one, leads over Col Basset to the winter sports resort, Sestriere.