Sudan (officially the Republic of Sudan) (Arabic: السودان al-Sūdān) is a country in northeastern Africa. It is the largest in the African continent and the Arab World, and tenth largest in the world by area. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, Kenya and Uganda to the southeast, Democratic Republic of the Congo and the Central African Republic to the southwest, Chad to the west and Libya to the northwest. The country's name derives from the Arabic Bilad-al-Sudan, literally "land of the blacks." Sudan has recently emerged as the world's most unstable country according to the Failed States Index, mainly due to its military dictatorship and the ongoing war in Darfur. Sudan is situated in northern Africa, bordering the Red Sea and it has a coastline of 853 km along the Red Sea. With an area of 2,505,810 square kilometres (967,499 sq mi), it is the largest country in the continent and the tenth largest in the world. It borders the countries of Central African Republic, Chad, Democratic Republic of the Congo, Egypt, Eritrea, Ethiopia, Kenya, Libya and Uganda. It is dominated by the River Nile and its tributaries. The terrain is generally flat plains, broken by several mountain ranges; in the west the Jebel Marra is the highest range; in the south is the highest mountain Mount Kinyeti Imatong, near the border with Uganda; in the east are the Red Sea Hills.