The Nile flows through Cairo and forms the Nile Delta in northern Egypt.
At about 6,650 kilometres, the Nile is commonly described as the longest river in the world, although measurements and definitions can make comparisons with the Amazon controversial. The river runs northward through northeastern Africa before entering the Mediterranean Sea.
Cairo stands on the Nile near the point where the river begins spreading into the broad, fertile delta. The White Nile and Blue Nile are its principal tributaries; they meet at Khartoum in Sudan. The Blue Nile rises in Ethiopia, while the White Nile’s farthest headwaters are associated with the Lake Victoria region.
Ancient Egyptian civilization depended on the river’s seasonal floods, which deposited fertile silt across the valley. The Aswan High Dam, completed in the 1960s, greatly reduced natural flooding and created Lake Nasser, while also providing hydroelectric power and water storage.