The Sahara was not always a desert. Periods of drought and humidity have alternated over time. For example, some Oldowan sites have been described in the Massif des Richât east of Ouadane. They were located on the banks of palaeolakes, such as El Beyedh or Guelb Er Richât. The most important sites are Wadi Akerdeil and Aftassa-Amzeili southeast of Zouerate. - These stone spheres come from El Beyedh in Mauritania. The large sphere has a diameter of 13 cm, the small one of 5.5 cm. (IFAN Collection, Dakar, Senegal) - 1969
