The Aterian is a Middle Stone Age (or Middle Palaeolithic) stone tool industry centered in North Africa, but also possibly found in Oman, the Thar Desert, Sahara (Saharan Aterian) and northeast Africa (Eastern Aterian). The earliest Aterian dates to c. 150,000 years ago, at the site of Ifri n'Ammar in Morocco. However, most of the early dates cluster around the beginning of the Last Interglacial, around 150,000 to 130,000 years ago, when the environment of North Africa began to ameliorate. The Aterian disappeared around 20,000 years ago.