The Issaouane Erg (sand sea), seen in this photograph from the International Space Station, is located in eastern Algeria between the Tinrhert Plateau to the north and the Fadnoun Plateau to the south. Ergs are vast areas of moving sand with little to no vegetation cover. Considered to be part of the Sahara Desert, the Issaouane Erg covers an area of more than 14,000 square miles. These complex dunes form the active southwestern border of the sand sea.
© National Aeronautics & Space Administration / Science & Society