Ugab River, Namibia

Namibia’s ephemeral Ugab River flows above ground for only a few days each year. Here, the ecologically important river passes through nearly vertical layers of thinly bedded limestone, sandstone, and siltstone.

image NASA/GSFC/METI/ERSDAC/JAROS,and U.S./Japan ASTER Science Team

Also imaged in Namibia : The Brandberg Massif is dome-shaped granite intrusion covers an area of 650 square kilmeters (250 square miles) and rises 2,573 meters (1.6 miles), and is the dominant geographic feature of the central Namib desert. Landsat Interactive Map.

Coastal winds create the tallest sand dunes in the world in Namib-Naukluft National Park, which is an ecological preserve in Namibia's vast Namib Desert.

Still in Africa, Mt Kilimanjaro is an extinct stratovolcano (with three peaks) in Kenya.

Another dry riverbed crossing an arid landscape is revealed as the Ghadamis River crosses in the Tinrhert Hamada Mountains near Ghadamis, Libya.