The Picos de Europa is a range of mountains some 20 km inland from the northern coast of Spain. It consists of three major massifs - Central, Eastern and Western (also known as the Picos de Cornión). The Central and Western massifs are separated by the mile-deep (1.5 km deep) Cares Gorge (Garganta del Cares), with the village of Caïn at its head. The waters in the Cares mostly arise from cave resurgences. Much of the water in the Cares river has been diverted into a hydroelectric scheme, with a closed canal running in the northern wall of the gorge to Carmamena. An access path next to the canal provides a spectacular walk.
The rocks are almost all limestone and glacial action has contributed to create an extremely impressive area of alpine karst reaching altitudes of 2400 m. The area is popular with mountaineers, climbers and mountain walkers. There is a good network of well-established mountain refuges. The best-known climbing site is the Naranjo de Bulnes.
The Picos de Europa contain many of Spain's deepest caves, including Torca del Cerro (−1400 m), Torca los Rebecos (−1255 m) and Sistema del Hitu (Xitu) (−1135 m). Discovery of new caves and their exploration still continues.
Most of the region is now protected as a single National Park in Cantabria, Asturias and León provinces of Spain; the Asturian part was Spain's first National Park. Access is via minor roads to each of the three massifs from the north and from the south to the teleferique at Fuente De and to Cain at the head of the Cares Gorge.