Africa's largest country in land area, Sudan is dominated by the Nile and its tributaries, with mountains rising along its Red Sea coast and along the western border with Chad. Sudan's name in Arabic means "land of the blacks."

Since independence from Britain in 1956, a north-south war has dominated Sudan's history, pitting Arab Muslims in the northern desert against black Christians and animists in the southern wetlands. Muslim Arabs control the government in Khartoum, but are only about 39 percent of the population. Blacks, or Africans, make up 52 percent of Sudanese, and are most numerous in southern and western Sudan. The country is further divided with hundreds of black, Arab, and non-Arab ethnicities, tribes, and languages.

Sudan's political history has been unstable. Gen. Muhammad Nimeiri, who seized control in the 1970s, was deposed in 1985. In 1989 another military coup, led by then-Col. Omar al-Bashir, toppled the elected government. The military dictatorship, so far, has been incapable of stopping the civil war. Indeed its intensity rose with the discovery and exploitation of oil fields in the south. In 2004 a rebel uprising by blacks in western Sudan's Dafur region brought army reprisals, creating 100,000 refugees. Pro-government Arab militias carried out systematic killings of Darfur's blacks—who are mostly Muslim.