The Tassili n’Ajjer (It is a name from the Berber language and its English name is: « Tassili Plateau ») is a mountain range in the Sahara desert in southeast Algeria, North Africa. The highest point is Adrar Afao, 2158 m. The nearest town is Djanet, about 10 km southwest of the range.
The range is composed largely of sandstone. Erosion in the area has resulted in nearly 300 natural rock arches being formed, along with many other spectacular landforms.
Because of the altitude and the water-holding properties of the sandstone, the vegetation is somewhat richer than the surrounding desert; it includes a very scattered woodland of the endangered endemic species Saharan Cypress and Saharan Myrtle in the higher eastern half of the range. The range is also noted for its prehistoric rock paintings and other ancient archaeological sites, dating from neolithic times when the local climate was much moister, with savannah rather than desert. The art depicts herds of cattle, large wild animals including crocodiles, and human activities such as hunting and dancing. The art has strong stylistic links to the pre-Nguni Art of South Africa and the region, executed in caves by the San Peoples before the year 1200 CE.