Darfur, a vast arid region of Sudan the size of France, has been wracked by civil war since February 2003, resulting in one of the world's worst humanitarian catastrophes.
The conflict pitting black tribal rebels against Sudan's regime, backed by Arab militias, left an estimated 300,000 dead in its first five years alone, according to the UN.
More recent figures are not available, but Khartoum said only 10,000 died.
More than one million are still displaced in camps, the UN says.
Darfur borders Chad, Libya, the Central African Republic and South Sudan in northeastern Africa, and has a population of six million. It was a sultanate until 1916 when it was incorporated into Sudan, then ruled by Britain and Egypt.
The region takes its name from one of its principal tribes, the Fur, and the Arabic word "Dar," meaning home.
The population comprises both peasant farmers and nomadic peoples spread over 500,000 square kilometres (200,000 square miles).
The region is a mix of desert, high plateaus and volcanic summits culminating in the 3,071 metres (10,134 feet) of the highest peak in the Jebel Marra mountains.
It contains considerable potential mineral wealth, including oil, uranium and copper, with cattle-rearing one of the main sources of income.
The region has long seen conflict between the nomadic and farming tribes.
However, there was no armed political movement until 2003, with the emergence of the Darfur Liberation Front which quickly changed its name to the Sudan Liberation Movement/Army (SLM/A).
A second major rebel group, the Justice and Equality Movement (JEM), emerged at about the same time.
War broke out in February 2003 when rebels revolted against what they say is the political and economic marginalisation of the region's black ethnic groups by the Arab-dominated Khartoum regime.
Khartoum responded by unleashing the Janjaweed, a militia of mounted gunmen dubbed "devils on horseback," which have been blamed for atrocities including murder, rape, looting and burning villages.
The conflict has no basis in religion, with Darfur's entire population -- made up of numerous Arab and African tribes -- being essentially both Muslim and Arabic speaking.
Although the level of violence has greatly diminished in recent years, clashes between rebels and the army, robberies, kidnappings and tribal violence frequently take place.
In July, 2011, the government signed the Doha Document for Peace in Darfur with the Liberation and Justice Movement, an alliance of rebel splinter factions
But the main rebel groups -- JEM and factions of the SLA -- did not sign.
Instead they, along with the SPLM-North rebel group from outside Darfur, ratified documents forming the new Sudanese Revolutionary Front dedicated to "popular uprising and armed rebellion" against the National Congress Party regime in Khartoum.
Eltigani Seisi, who heads the Darfur Regional Authority set up in 2011 to implement the Doha agreement, says the economic recovery of Darfur needs an estimated $6 billion (4.5 billion euros). He appealed for international support, 10 years after the outbreak of war.
A hybrid African Union-United Nations force called UNAMID arrived in the region in 2007, and currently numbers about 19,000 soldiers and police, one of the world's biggest peacekeeping operations.
Humanitarian workers, diplomats and journalists face many restrictions when seeking to travel in the region.