Erg Chigaga is the largest and still untouched of the major ergs in Morocco; the other is Erg Chebbi near Merzouga. This erg made of beautiful sand dunes is located in the Drâa-Tafilalet area about 45 km west of the small rural oasis town of M'Hamid El Ghizlane, itself located about 98 km south of the town of Zagora. Wikipedia