The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately 6,000 kilometres in length that runs from central Mozambique in South East Africa to northern Syria.
The East African rift has two branches, the Western Rift Valley and the Eastern Rift Valley.
The Western Rift, also called the Albertine Rift, is edged by some of the highest mountains in Africa, including the Virunga Mountains, Mitumba Mountains, and Ruwenzori Range. It contains the Rift Valley lakes, which include some of the deepest lakes in the world (up to 1,470 metres deep at Lake Tanganyika).
As the lakes in the Eastern Rift have no outlet to the sea and tend to be shallow, they have a high mineral content as the evaporation of water leaves the salts behind.
For example, Lake Magadi has high concentrations of soda (sodium carbonate) and Lake Elmenteita, Lake Bogoria, and Lake Nakuru are all strongly alkaline, while the freshwater springs supplying Lake Naivasha are essential to support its current biological variety.
The Ethiopian Rift Valley lakes are the northernmost of the African Rift Valley lakes. The Ethiopian Rift Valley lakes occupy the floor of the rift valley between the two highlands. The Ethiopian Rift Valley Lakes are of great importance to Ethiopia's economy, as well as being essential to the survival of the local people.
The Rift Valley varies mostly between 600 and 900 metres in depth, with a maximum of 2,700 metres at the Gikuyu and Mau escarpments.
Like the Sahara, the Equator or the tropical rain forest, the Great Rift Valley offers a unique theme to a transcontinental journey.
