Starting in Erfoud, after many kilometres of stony desert making for a rather harsh landscape, one is struck by the lushness of the pink and golden sand dunes of Erg Chebbi. This is the only erg (dune sea) in the Moroccan Sahara. It stretches from north to south for about 40km, to the west of the Ziz River palm groves, its sand mass rising at times to 170m.