The Afar Triangle is a geological depression that is caused by the Afar Triple Junction, which is part of the Great Rift Valley. It overlaps Eritrea, Djibouti and the entire Afar Region of Ethiopia. The depression is bordered by the Ethiopian Plateau and escarpment to the west, by the Danakil block to the north-east (between it and the Red Sea), by the Somalian Plateau and escarpment to the south, and by the Ali-Sabieh block (adjoining the Somalian Plateau) to the south-east. The Afar Triangle includes the lowest point in Africa, Lake Asal (155 metres or 509 feet below sea level) in Djibouti. The Awash River is the main waterflow into the area, where it ends in a chain of lakes that increase in salinity. The northern part of the Afar Triangle is also known as the Danakil Depression.