evidence: Lake Nyasa, also called Lake Malawi, southernmost and third largest of the East African Rift Valley lakes of East Africa, lying in a deep trough mainly within Malawi and covers three regions of Tanzania including Mbeya, Njombe and Ruvuma. Lake Nyasa (Nyasa means "lake") is located at the south-west of Tanzania, The lake lies in three countries’ territory; Tanzania and Malawi. However, it is bordered by three countries, Tanzania , Malawi and Mozambique. It is the third largest in Africa (after Lake Victoria and lake Tanganyika) with 550 kilometers length and 75 kilometers width, covering an area of more than 11,400 square kilometers. In some parts, the lake is as deep as 700 meters. [...] Lake Nyasa is also among the Great Rift Valley’s lakes, which shares some of the characteristics with lake Tanganyika. The lake has a distinctive characteristic: 14 rivers pouring their waters into the lake, and only one river which flows out to the sea, River Shire.