A tough and complete circuit allowing to test one's endurance by connecting the departures of Amplepuis at Clos du Crêt and Tarare. This long loop goes from the Loire watershed to the Rhône watershed, crossing the watershed twice. After a first part with lots of elevation changesuntil the Col du Pin Bouchain, the passage of the Turdine valley at the Joux dam offers a deserved rest, before a new effort to reach Notre-Dame de la Roche. The reward is the view on Tarare and a passage at the foot of the four windmills of Valsonne.