Algeria's Tassili n'Ajjer National Park
Orange-hued dunes mantle dark sandstone on the northern edge of Algeria's Tassili n'Ajjer National Park (//world-heritage-datasheets.unep-wcmc.org/datasheet/output/site/tassili-najjer-national-park/) in this photo from an Earth-facing external camera mounted on the International Space Station. The park's name translates to "plateau of chasms", and these signature ravines wind through the rock in the right of the image. On the left, wisps of cloud overlie a dune field that has swept over the low-lying regions north of the Fadnoun Plateau.
Rising to elevations of over 1,500 meters (4,900 feet) on average, the current plateau has been shaped by thousands of years of water and wind erosion. Though the area is now hyper-arid, ancient rivers once cut narrow canyons almost 240 meters (800 feet) deep into the sandstone as they flowed north toward lakes that filled what are now large dune fields called ergs ("sand seas"). Issaouane Erg, shown above, contains some of the tallest star dunes on Earth. Another erosional feature is the "forest of rock" (//www.archmillennium.net/tassili_national_park.htm) large pillars of resistant sandstone that have remained as strong winds eroded the softer surrounding rock.
The town of Illizi, home to more than 17,000 people, stands at the northern edge of the plateau and continues a chain of human habitation in the region that dates back to 10,000 BCE. Rock engravings mark this long history and have made the plateau a rich area of study for archeologists and anthropologists.