The Omo River (; also called Omo-Bottego) in southern Ethiopia is the largest Ethiopian river outside the Nile Basin. Its course is entirely contained within the boundaries of Ethiopia, and it empties into Lake Turkana on the border with Kenya. The river is the principal stream of an endorheic drainage basin, the Turkana Basin. The river basin is famous for its large number of early hominid fossils and archeological findings such as early stone tools, leading to its inclusion on the UNESCO World Heritage List in 1980. Geography The Omo River forms through the confluence of the Gibe River, by far the largest total tributary of the Omo River, and the Wabe River, the largest left-bank tributary of the Omo at . Given their sizes, lengths and courses one might consider both the Omo and the Gibe rivers to be one and the same river but with different names. Consequently, the whole river basin is sometimes called the Omo-Gibe River Basin. This river basin includes part of the western Oromia Region and the middle of the Southern Nations, Nationalities, and People's Region. Its course is generally to the south, however with a major bend to the west at about 7° N 37° 30' E to about 36° E where it turns south until 5° 30' N where it makes a large S- bend then resumes its southerly course to Lake Turkana. According to materials published by the Ethiopian Central Statistical Agency, the Omo-Bottego River is 760 kilometers long. In its course the Omo-Bottego has a total fall of about 700 m from the confluence of the Gibe and Wabe rivers at 1060 m to 360 m at lake-level, and is consequently a rapid stream in its upper reaches, being broken by the Kokobi and other falls, and navigable only for a short distance above where it empties into Lake Turkana, one of the lakes of the Gregory Rift. The Spectrum Guide to Ethiopia describes it as a popular site for white-water rafting in September and October, when the river is still high from the rainy season. Its most important tributary is the Gibe River; smaller tributaries include the Wabi, Denchya, Gojeb, Mui and Usno rivers. The Omo-Bottego River formed the eastern boundaries for the former kingdoms of Janjero, and Garo. The Omo also flows past the Mago and Omo National Parks, which are known for their wildlife. Many animals live