The little sister of the Authie River, the Canche is a slow-flowing river whose waters run into a marsh. In this untamed setting, the green valley broadens out into gentle slopes scattered with elongated houses with whitewashed walls. Between Touquet-Paris-Plage and Hesdin, don't miss the ramparts of Montreuil and the De Neuville Monastery. In Frévent, the Wintenberger Museum revisits the hard labour endured by the peasants and workers of Ternois. The Canche ultimately flows into the Côte d'Opale in Étaples.