Quietophone's video: 3 Triangular Postage Stamps from Chad and Congo

Triangular Chadian and Congolese stamps. Chad; Arabic: تشاد‎‎ Tshād; French: Tchad, officially the Republic of Chad (Arabic: جمهورية تشاد‎‎ Jumhūrīyat Tshād; French: République du Tchad lit. "Republic of the Chad", is a landlocked country in Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon and Nigeria to the southwest and Niger to the west. It is the fifth largest country in Africa in terms of area. Chad has several regions: a desert zone in the north, an arid Sahelian belt in the centre and a more fertile Sudanian Savanna zone in the south. Lake Chad, after which the country is named, is the largest wetland in Chad and the second-largest in Africa. The capital N'Djamena is the largest city. Chad's official languages are Arabic and French. Chad is home to over 200 different ethnic and linguistic groups. The religions of Chad are Islam (at 55%), followed by Christianity (at 40%). Beginning in the 7th millennium BCE, human populations moved into the Chadian basin in great numbers. By the end of the 1st millennium AD, a series of states and empires had risen and fallen in Chad's Sahelian strip, each focused on controlling the trans-Saharan trade routes that passed through the region. France conquered the territory by 1920 and incorporated it as part of French Equatorial Africa. In 1960, Chad obtained independence under the leadership of François Tombalbaye. Resentment towards his policies in the Muslim north culminated in the eruption of a long-lasting civil war in 1965. In 1979 the rebels conquered the capital and put an end to the south's hegemony. However, the rebel commanders fought amongst themselves until Hissène Habré defeated his rivals. He was overthrown in 1990 by his general Idriss Déby. Since 2003 the Darfur crisis in Sudan has spilt over the border and destabilised the nation, with hundreds of thousands of Sudanese refugees living in and around camps in eastern Chad. Unsustainable high birth rates and a lack of agriculture let the country persist in poverty. While many political parties are active, power lies firmly in the hands of President Déby and his political party, the Patriotic Salvation Movement. Chad remains plagued by political violence and recurrent attempted coups d'état. Chad is one of the poorest and most corrupt countries in the world; most inhabitants live in poverty as subsistence herders and farmers. Since 2003 crude oil has become the country's primary source of export earnings, superseding the traditional cotton industry. In the 7th millennium BC, ecological conditions in the northern half of Chadian territory favored human settlement, and the region experienced a strong population increase. Some of the most important African archaeological sites are found in Chad, mainly in the Borkou-Ennedi-Tibesti Region; some date to earlier than 2000 BC.