Trail of el Cares desde Caín Activity · Posada de Valdeón, La Montaña de Riaño, León The most walked path in the Picos de Europa starts at Caín de Valdeón and climbs the gorge of the river Cares towards Asturias along a way carved into the vertical wall for the maintenance of a hydroelectric channel. Photo: Cruccone (CC BY 3.0) What to see and do in Posada de Valdeón