Access: from Barbastro, follow the indications for Huesca and after about 15 km take the road on the right heading for Bierge. Once in Bierge, take the road to Huesca, Yaso and Morrone; after about 15 km a bridge crosses the Rio Formiga. Just after the bridge there is a large parking.

Approach: cross the river and, on the left bank, take the path that follows a little irrigation pipe and gradually rises along the river a few meters below. Go on for about 25’ and reach La Cuevas de las Polverosas, a huge cave once used as hut. From here, the path goes on with some short horizontal climbs until it reaches the first bolt that allows to get into the bed of the river.

Coming Back: after the last rope descent go on for a few minutes until the river bed becomes really full of vegetation. On the left bank take a little path leading to the approach main path.