Which is the longest river?

The Nile River has traditionally held the title of world's longest river at approximately 6,650 km (4,130 miles), flowing northward through 11 countries from its headwaters in Burundi/Rwanda to its delta in Egypt. However, the Amazon River's length is increasingly disputed: depending on which tributary is measured as its source, estimates range from 6,400 to 7,062 km — potentially making it longer than the Nile. A 2007 Brazilian-Peruvian expedition claimed the Amazon stretches 6,992 km when measured from its farthest source in the Andes. While the Amazon is shorter (or comparable) in length, it absolutely dominates in volume: it discharges 209,000 m³/s — about 20% of all river water entering the oceans and more than the next seven largest rivers combined.