The Río Vero is not a big river, but it has spent a very long time doing something clever with the limestone of the Sierra de Guara. Above Alquézar it has cut a gorge that narrows to a few metres in places and widens again into pools the colour of bottle glass, and the plateau on both sides is a dry country of box, holm oak and aromatic scrub that bears almost no relation to the water below. Arpán is a small side-valley three kilometres from the village, a short walk off the road, and its shelter is one of several in the Vero canyon system that carry painted figures from the ancient hunters of the Levantine tradition.
Riding out to it is a lesson in how quickly the Pyrenean foothills change character. Leave Barbastro among vineyards and peach orchards, and within half an hour the road is climbing through a rocky landscape with the first sharp ridges of the Guara rising ahead. The bends tighten, the surface is generally good, and the traffic consists mostly of vans carrying canyoning gear. Late spring and early autumn are kindest. In August the plateau bakes and the gorge floor is full of people; in January the shady curves keep frost until noon.
Alquézar itself deserves a longer look than the average rider gives it. The village hangs on a rocky spur above the river, topped by a collegiate church that began life as a Muslim fortress and was converted into a Christian stronghold in the eleventh century, and the lanes between the stone houses are steep and narrow enough that you leave the bike at the entrance. There are terraces for coffee and a few places that serve local lamb, and the walkways bolted to the canyon wall are well worth an hour.
Fuel is the weak point. Salas Altas and Angüés are small villages with bars. Treat the shelter with the care it needs; the Aragonese government protects the rock art of the Vero as a cultural park, and some sites are open only with a guide.