arid lowland of northern Ethiopia and southeastern Eritrea, bordering Djibouti. It lies at the northern extreme of the Great Rift Valley and the Awash River. Live volcanoes (often called the Denakil Alps) separate it from the Red Sea. Any water that comes into the plain evaporates there; no streams flow out from it. The Kobar Sink, a huge basin in the northern part of the plain, drops to 381 feet (116 m) below sea level. The Denakil Plain was formed by the evaporation of an inland sea. About 450 square miles (1,200 square km) is covered by salt; (salt) salt reserves are estimated at more than 1,000,000 tons (1,120,000 metric tons). The salt is cut into bars and carried by mule to other parts of Ethiopia and Eritrea. Nomadic pastoralists, related to the Afar people of Djibouti, are virtually the plain's only inhabitants. In the southern part of the plain, in Ethiopia, lies the Mille-Sardo Wildlife Reserve (1973), which covers 3,385 square miles (8,766 square km).