The sand dunes of Erg Chebbi are the tallest and most well-known in Morocco. They span an area 22 km long and 5 km wide, and rise up to 150 m. However, they are not the biggest by area, for that title goes to the only other sand dunes in Morocco, Erg Chigaga near M'hamid, which cover a bigger area, but only rise to 50 m.
Erg Chebbi (and for that matter Erg Chigaga too) is the iconic picture of the Sahara, as a stunning sea of orange sand dunes. However, technically none of them are in the Sahara.
The small town Merzouga is located literally at the foot of the dunes of Erg Chebbi and is the action center for any sand activity you can think of. Though there are auberge in town, many choose to stay under the stars in a desert camp.