Source of the Sella river Nature · Oseja de Sajambre, La Montaña de Riaño, León The Sella rises at the Fuente del Infierno, within the municipal boundary of Oseja de Sajambre (León), though its true source lies at the site of Junseya; from here it runs 66 kilometres before reaching the Cantabrian Sea, forming the ría of Ribadesella, after carving the gorge of Los Beyos and serving as the boundary between several Asturian concejos. The Count of Saint-Saud described the rocky amphitheatre of its headwaters, dominated by peaks such as the Pozúa, at 1,923 metres, and the Pico Jario, at 1,908, as «a vast circular basin with a rocky cone majestically placed at its centre». Downstream, between Arriondas and Ribadesella, the Descenso Internacional del Sella has been held since 1930, a canoeing event that gathers a great popular festival every August. Photo: Wamba Wambez (CC BY-SA 3.0) What to see and do in Oseja de Sajambre