The Nile is traditionally regarded as the longest river in the world.
The river flows northward through northeastern Africa for roughly 6,650 kilometres, reaching the Mediterranean Sea. Its main branches are the White Nile, associated with the Lake Victoria region, and the Blue Nile, which rises in Ethiopia and supplies much of the sediment and seasonal flow.
The Nile’s annual flooding supported ancient Egyptian agriculture and helped make the river valley one of the earliest centers of urban civilization. The Aswan High Dam, completed in 1970, greatly reduced natural flooding while creating Lake Nasser and generating hydroelectric power.
Some modern measurements argue that the Amazon may be longer, depending on which headwater and mouth are selected. For standard general-knowledge references, however, the Nile remains the conventional answer to the longest-river question.