a plateau in Africa, in the Algerian Sahara, situated to the northeast of the Ahaggar plateau. The Tassili-n-Ajjer plateau is composed of sandstones covered with lava and volcanic cones with elevations of up to 2,158 m (Mount Azao). It is dissected by deep wadis, along whose beds grow trees and grasses.
Tassili-n-Ajjer is one of the oldest centers of human habitation in the Sahara; the plateau’s numerous caves and projections were used as dwellings. A major group of ancient rock paintings, as well as Neolithic implements and pottery, was discovered at Tassili-n-Ajjer. The most detailed investigation of these findings was made by the French expedition led by H. Lhote in 1956–57. Tens of thousands of fragments of paintings from different periods have been preserved. They range from primitive drawings of elephants, giraffes, and hippopotamuses dating from approximately the sixth and fifth millennia B.C. and group scenes of hunting, warfare, and herding dating from the fourth millennium B.C. to stylized drawings of camels dating from the first centuries of the Common Era.