Chad is one of the 47 landlocked countries in the world and is located in North Central Africa, measuring 1,284,000 square kilometers (495,755 sq mi), nearly twice the size of France and slightly more than three times the size of California. Most of its ethnically and linguistically diverse population lives in the south, with densities ranging from 54 persons per square kilometer in the Logone River basin to 0.1 persons in the northern B.E.T. (Borkou-Ennedi-Tibesti) desert region, which itself is larger than France. The capital city of N'Djaména, situated at the confluence of the Chari and Logone Rivers, is cosmopolitan in nature, with a current population in excess of 700,000 people.
The Sahel region or Sahelian acacia savanna is a biogeographical region in Africa. It is the transition zone between the more humid Sudanian savannas to its south and the drier Sahara to the north. The Sahel has a hot semi-arid climate and stretches across the southernmost latitudes of North Africa between the Atlantic Ocean and the Red Sea. Although geographically located in the tropics, the Sahel does not have a tropical climate.
The Sahara is a desert spanning across North Africa. With an area of 9,200,000 square kilometres (3,600,000 sq mi), it is the largest hot desert in the world and the third-largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic.
Sudan is the geographical region to the south of the Sahara, stretching from Western Africa to Central and Eastern Africa. The name derives from the Arabic bilād as-sūdān and arḍ as-sūdān, both meaning "the lands of the Black [Africans]", referring to West Africa and northern Central Africa.
Trans-Saharan trade is trade between sub-Saharan Africa and North Africa that requires travel across the Sahara. Though this trade began in prehistoric times, the peak of trade extended from the 8th century until the early 17th century CE. The Sahara once had a different climate and environment. In Libya and Algeria, from at least 7000 BCE, pastoralism, large settlements and pottery were present. Cattle were introduced to the Central Sahara (Ahaggar) between 4000 to 3500 BCE. Remarkable rock paintings in arid regions portray flora and fauna that are not present in the modern desert.
The Islamization of the Sudan region (Sahel) encompasses a prolonged period of religious conversion, through military conquest and trade relations, spanning the 8th to 16th centuries.
The East Sudanian savanna is a hot, seasonally dry tropical savanna ecoregion of Central and East Africa.
The Northern Congolian forest–savanna mosaic is a forest and savanna ecoregion of central Africa. It extends east and west across central Africa, covering parts of Cameroon, Central African Republic, Democratic Republic of the Congo, South Sudan, and Uganda. It is part of the belt of transitional forest-savanna mosaic that lie between Africa's moist equatorial Guineo-Congolian forests and the tropical dry forests, savannas, and grasslands to the north and south.
Mauritania's wildlife has two main influences as the country lies in two biogeographic realms. The north sits in the Palearctic which extends south from the Sahara to roughly 19° north latitude and the south is in the Afrotropic realm. Additionally, Mauritania is an important wintering area for numerous birds which migrate from the Palearctic.
The Trans-Sahara Highway or TAH 2, formally the Trans-Saharan Road Corridor (TSR), and also known as the African Unity Road, is a transnational infrastructure project to facilitate trade, transportation, and regional integration among six African countries: Algeria, Chad, Mali, Niger, Nigeria, and Tunisia. It runs roughly 4,500 km north to south across the Sahara desert from Algiers, Algeria on the Mediterranean coast of North Africa to Lagos, Nigeria on the Atlantic coast of West Africa; subsequently, it is sometimes known as the Algiers–Lagos Highway or Lagos–Algiers Highway.
The South Saharan steppe and woodlands, also known as the South Sahara desert, is a deserts and xeric shrublands ecoregion of northern Africa. This band is a transitional region between the Sahara's very arid center to the north, and the wetter Sahelian Acacia savanna ecoregion to the south. In pre-modern times, the grasslands were grazed by migratory gazelles and other ungulates after the rainfalls. More recently, over-grazing by domestic livestock have degraded the territory. Despite the name of the ecoregion, there are few 'woodlands' in the area; those that exist are generally acacia and shrubs along rivers and in wadis.
A large-scale, drought-induced famine occurred in Africa's Sahel region and many parts of the neighbouring Sénégal River Area from February to August 2010. It is one of many famines to have hit the region in recent times.
The West Sudanian savanna is a tropical savanna ecoregion that extends across West Africa.
The Trans-Saharan slave trade, part of the Arab slave trade, was a slave trade in which slaves were mainly transported across the Sahara. Most were moved from sub-Saharan Africa to North Africa to be sold to Mediterranean and Middle Eastern civilizations; a small percentage went the other direction. Estimates of the total number of black slaves moved from sub-Saharan Africa to the Arab world range from 6-10 million, and the trans-Saharan trade routes conveyed a significant number of this total, with one estimate tallying around 7.2 million slaves crossing the Sahara from the mid-7th century until the 20th century when it was abolished. The Arabs managed and operated the trans-Saharan slave trade, although Berbers were also actively involved. Alongside Black Africans, Turks, Iranians, Europeans and Berbers were among the people traded by the Arabs, with the trade being practised throughout the Arab world, primarily in Western Asia, North Africa, East Africa, and Europe.
