Algeria's mountainous Tassili region, bordering Niger to the south, is situated in the far south-east of this vast country.
The region, with Djanet at its heart, is distinguished by its towering dunes of sand, its sheer-sided canyons and its engrossing "forests of rock" - not to mention its old ksars, oases, palm groves, gueltas and natural springs.
The Tassili - "plateau of the rivers" in Arabic - is an open-air treasure-trove of more than 15,000 rock carvings and cave paintings that depict pre-historic crocodiles, cattle and giraffes.
Tadrart is a particularly beautiful region in this remote part of Algeria's vast Sahara.