Tilemsi

The Tilemsi valley stretches north from Gao towards the Adrar des Ifoghas. This broad depression follows the bed of an ancient river that once flowed to the Niger; its dry course passes through the southern Sahara. Archaeological finds in the valley reveal a much longer history of human occupation than its barren appearance might suggest. It forms a natural passage between the rocky northern highlands and the Niger bend, where Gao grew into a great trading centre.