The Guelta d’Archei is probably the most famous guelta in the Sahara. It is located in the Ennedi Plateau, in north-eastern Chad, south-east of the town of Fada. The Guelta d’Archei is inhabited by several kinds of animals, most notably the Nile crocodile (Crocodylus niloticus Laurenti). Middle Holocene remains, as well as rock paintings, indicate that this species once thrived across most of today’s Sahara Desert and in swamps and rivers along South Mediterranean shores. The small group of surviving crocodiles in the Guelta d’Archei represents one of the last colonies known in the Sahara today; the Tagant Plateau colony in Mauritania has likely been extinct since 1996.It is a barren place, away from beaten paths; reaching it by land requires a 4×4 and at least four days’ travel from n’Djamena, Chad’s capital. The place depicted in the picture can only be reached by a few hours’ trek from the nearest point a 4×4 can approach.