the second largest of the continents, on the Mediterranean in the north, the Atlantic in the west, and the Red Sea, Gulf of Aden, and Indian Ocean in the east. The Sahara desert divides the continent unequally into North Africa (an early centre of civilization, in close contact with Europe and W Asia, now inhabited chiefly by Arabs) and Africa south of the Sahara (relatively isolated from the rest of the world until the 19th century and inhabited chiefly by dark-skinned peoples). It was colonized mainly in the 18th and 19th centuries by Europeans and now comprises independent nations. The largest lake is Lake Victoria and the chief rivers are the Nile, Niger, Congo, and Zambezi. Pop: 1 100 000 000 (2013 est). Area: about 30 300 000 sq km (11 700 000 sq miles)