Carved by the River Sella out of an exceptionally thick layer of limestone, the river rushing down this 10km-long defile is too fast-flowing for anything except the occasional tree to have put down roots on its sides. It is however wide enough for the sun's rays to sparkle off its precipitous waters from time to time.

This pass of the Picos de Europa chain, at an altitude of 1 290m, commands a scenic panorama of the Sajambre Valley. The descent begins with tight hairpin bends in full view of the western range. The road becomes more spectacular as you reach the formidable rock wall through which the Sella has hollowed its course.

This pass (1 562m) leads up to a vista of the three ranges of the Parque Nacional de los Picos de Europa. In the foreground to the right can be seen the two summits of the central range: the Cabén de Remoña and the Torre de Salinas. In the distance the village of Santa Marina de Valdeón nestles in a hollow.

This small 10C Mozarabic church is surrounded by poplars and dominated by high cliffs. The belltower and porch are later additions. The three vaulted naves rest on horseshoe arches. Note the Corinthian capitals.