Tanzania is a country in East Africa that is part of the African Great Lakes region. Its official name is the United Republic of Tanzania. Uganda is to the north, Kenya is to the northeast, the Comoro Islands are to the east, the Indian Ocean is to the east, Mozambique and Malawi are to the south, Zambia is to the southwest, and Rwanda, Burundi, and the Democratic Republic of the Congo are to the west. Mount Kilimanjaro, Africa's highest peak, is located in Tanzania's northeastern region. Many significant hominid fossils, including 6-million-year-old Pliocene hominid fossils, have been discovered in Tanzania. The Australopithecus species once roamed all of Africa, and the oldest fossils of the genus Homo can be found near Lake Olduvai. Following the 1.8 million-year-old rise of Homo erectus, mankind spread across the Old World, and later into the New World and Australia as Homo sapiens. H. H. Sapiens have conquered Africa and consumed humanity's older archaic species and subspecies. Prehistoric migrations into Tanzania later in the Stone and Bronze Age included Southern Cushitic speakers who migrated south from present-day Ethiopia; Eastern Cushitic people who moved north of Lake Turkana between 2,000 and 4,000 years ago; and the Southern Nilotes, including the Datoog, who emerged between 2,900 and 2,40 years ago from the present-day South Sudan–Ethiopia border area. These migrations occurred at the same time as the Mashariki Bantu from West Africa settled in the Lake Victoria and Lake Tanganyika regions. Between 2,300 and 1,700 years ago, they spread through the rest of Tanzania. German rule in mainland Tanzania started in the late 19th century, when Germany founded German East Africa. After World War I, British rule was established, with the mainland governed as Tanganyika and the Zanzibar Archipelago governed as a separate colonial jurisdiction. The two countries combined in 1964 to create the United Republic of Tanzania, following their independence in 1961 and 1963, respectively. Tanzania joined the British Commonwealth in 1961 as a single republic, and it is still a member of the Commonwealth today. Tanzania's population was projected by the United Nations to be 56.31 million in 2018, marginally less than South Africa's, making it the second most populated country entirely south of the Equator. Around 120 cultural, linguistic, and religious groups make up the population. Tanzania is a presidential republican republic, and Dodoma has served as the country's official capital since 1996, housing the president's office, the National Assembly, and all government ministries. Dar es Salaam, the former capital, still houses most government offices and serves as the country's largest city, main port, and commercial hub. Tanzania is a de facto one-party dictatorship, with the Chama Cha Mapinduzi Democratic Socialist Party in control.