History of Chad Africa's major language groupings south of the Sahara Desert (except Khoisan, which is not considered a valid genetic grouping anyway), i. e. the Afro-Asiatic, Nilo-Saharan and Niger–Congo phyla, originated in prehistoric times in a narrow band between Lake Chad and the Nile Valley. The origins of Chad's peoples, however, remain unclear. Several of the proven archaeological sites have been only partially studied, and other sites of great potential have yet to be mapped. At the end of the 1st millennium AD, the formation of states began across central Chad in the sahelian zone between the desert and the savanna. For
Chad–Cameroon Petroleum Development and Pipeline Project human trafficking. Oil exploitation is estimated at a potential 1.5 billion barrels, and Chinese companies are currently developing an oil refinery and another pipeline in the country. The Tchad Oil Transportation Company (TOTCO) manages the pipeline within Chad that is owned by the country. TOTCO is incorporated in Tchad, and is a joint venture between Chad and the Upstream Consortium. The Republic of Cameroon has been ruled by President Paul Biya since November 6, 1982. A relatively peaceful and stable nation, Cameroon is a republic with a multiparty presidential regime. Although there are presidential elections every seven years, there are