Just before the "Tunnel du Légionnaire", hewn out of the rock, the valley narrows and the corniche road enters a long corridor, whose bare walls frame a string of narrow palm groves dominated by ksour (Berber castles) and Ifri Kasbah. The wild harshness of this landscape strikes the imagination. In a bend in the road, you come to Hassan Addakhil Dam, then the road goes around the winding banks of the reservoir, whose red walls plunge into emerald green water; you then reach Errachidia.