Roll out of Uzeste and the castles come first: Château des Jaubertes, then Château du Hamel, each a castle in its own right along the way. Between them the route drops by La Garonne, the river, before following the Canal Latéral à la Garonne. It's 68.4 km of paved riding with 403 m of climbing, and the loop brings you back to Uzeste.
