Séfar (in Arabic: سيفار) is an ancient city in the heart of the Tassili n'Ajjer mountain range in Algeria, more than 2,400 km south of Algiers and very close to the Libyan border. Séfar is the largest troglodyte city in the world, with several thousand fossilized houses. Very few travelers go there given its geographical remoteness and especially because of the difficulties of access to the site. The site is full of several paintings, some of which date back more than 12,000 years, mostly depicting animals and scenes of hunting or daily life which testify that this hostile place has not always been an inhabited desert. Local superstition suggests that the site is inhabited by djins, no doubt in connection with the strange paintings found on the site.

In February 1966, Pierre Mazeaud and Lucien Berardini attempted a difficult first ascent to one of the summits of Garet El Djenoun, in the Hoggar massif, a mountain range located west of the Sahara, in the south of Algeria. The mountain has been preserved intact since Roger Frison-Roche's expedition in 1935. The documentary, superbly filmed by René Vernadet, won the Grand Prix at the Trento Film Festival in 1966.