Tassili N’Ajjer is the North Easterly part of the Central Sahara Mountains. It’s made up of sandstone plateaux (“tassili”) surrounded by vast stretches of dunes: the “ergs”.
Due to the desert climate and intense erosion, the landscape is unbelievable: abrupt cliffs, deep and narrow canyons, “stone forests”, sandstone columns (or mushrooms), burnt and torn looking rocks….
The climate is particularly arid and temperature differences are very high. In winter, nights are freezing and the daytime pleasant, in summer (May, June and July) temperatures can get up to 40°. However,Tassili is privileged due to it’s altitude, the plateau is at around 2000m at places and Djanet is at 1100m. The very dry air helps support even the highest temperatures. Let’s just add that rain is rare.
Conditions have not always been like this; the Sahara has known several climate changes. The relief, the fauna and flora have kept traces of this past.
Remains; much as the desert is arid and harsh nowadays, excepting a few preserved areas, traces of more clement periods abound. This contrast between what is the desert today and remains of past civilisations is the major interest of Tassili; ochre paintings and engravings of all sizes by thousands.