. . . "sand wall" . . "defensive walls" . . . . "Moroccan Western Sahara Wall" . . . . "Moroccan Wall" . . . "border wall" . . . "six mostly sand barriers" . . "the extensive sand-berm in the desert" . "Berm" . . . "Moroccan wall" . "Moroccan Western Sahara Wall" . . . . . "defensive wall" .