Chad. Ennedi rock art. The characteristic Earth up witness; Mount Deli in the southwest of Archei; houses at its foot a source with such a small flow; so constant; that a year can pass between each rain before it dries up; as well as prehistoric rock art sites and a vast necropolis with hundreds of tumulus. "Deli is the name given by the Bideyat; because it is the name of a genius who lives on the rock. According to legend; the ascent of this rock is very difficult; but if one succeeds; one finds at the top a palm grove; water; various objects. However; it is impossible to descend from it; and the reckless genius who attempted it must resign himself to death" (Burthe d' Annelet; 1932)