The Guelta d'Archei is an oasis, or rather a gutter, in the heart of the Sahara desert. A gutter is a peculiar type of wetland, typical of the desert regions, which is formed when groundwater in lowland depressions dumps to the surface and creates permanent pools and reservoirs. The Guelta d'Archei is located on the plateau of Ennedi, in the north-east of Chad, hidden behind a canyon. Its waters are protected by the imposing sandstone cliffs typical of this region. Every day, hundreds of camels are taken to the deep waters of the gutter so they drink and rest. The manure of thousands of camels excreted for hundreds of years have turned the water into a black color.
