Boltaña is a small town of nine hundred people in the Sobrarbe, the valley country at the foot of the high Pyrenees, and from its edge the view north is dominated by the great limestone massifs of the Monte Perdido range, often white with snow into early summer. The shelter at Mascún II lies about twenty kilometres away, in the quieter, lower hills of the Sierra de Guara. It carries painting in the Levantine tradition, protected by UNESCO as part of the rock art of the Mediterranean basin in Spain, and the ride links it with El Remosillo, another site in the canyons.
Between the two lies a whole range of riding. Aínsa, a short way north of Boltaña, has one of the most handsome medieval squares in Aragón, a great arcaded space of stone beneath a castle, and its old town is a lovely place for lunch. Beyond, the road climbs into the Pyrenees, with passes, gorges and a succession of long, flowing curves. The Sobrarbe is also a land of Romanesque churches, small and stone-built, and of bears, vultures and chamois in the mountains.
Mascún itself is the southern, drier part of the story. The canyon is deep and narrow, with warm, golden walls, and the vegetation is holm oak, box and pine. The silence is deep, broken only by the call of a raven or the rush of water in spring.
The roads are narrow, twisty and wonderful, rising and dropping between villages in a series of tight bends, with surfaces that can be patchy and gravelly. Traffic is light, and the main hazards are livestock and fallen rock. Spring and autumn are the best seasons, and in winter, ice can linger on shaded corners.
Boltaña has the basics, though fuel is better found at Aínsa or at Huesca, a city of over fifty thousand about thirty-two kilometres away. Angüés and Alquézar are small. Bring water and a warm layer.