This enormous gash in the rock is uniquely beautiful, forged as it is by a gorge. You can cross it by a primitive stone bridge that only has one arch, consequence of the erosive action of the Asabón river. You can get there from Villalangua, crossing the river and taking a sign-boarded track. A seven-metre water-fall greets you after walking for about 15 minutes. You should see numerous eagles on the way. Close to the gully you can observe the Osqueta Pass in the shape of a W.