The primary landform in the Sahara Desert is the erg, which refers to large areas of sand dunes. These dunes can reach heights of up to several hundred feet and are shaped by wind action and desert conditions. The Sahara also features other landforms like hamadas (stony plateaus) and reg (gravel plains), but the extensive sandy expanses define its landscape. The Sahara is the largest hot desert in the world and plays a crucial role in regional climate and ecology.