Congosto de Ventamillo is the huge limestone canyon formed by river Ésera which makes up the main entrance by car to Benasque valley. This itinerary first climbs up to Chía and then borders the upper part of the canyon with stunning panoramic views and some singletrack sections. In Seira the route crosses the river and the national road and starts the steep ascent to Gabás, where another beautiful singletrack goes down to El Run and later to Castejón de Sos. A more difficult variant goes through the very heart of the cliffs by a narrow and suspended trail with some technical steps that will satisfy the toughest bikers.