Nile traditionally considered world's longest river at 6,650 km. Amazon's length debated between 6,400 km and 7,088 km. Amazon's length measured by adding Pará estuary and tidal canals
Amazon River is world's largest by discharge volume, 6,500 km long. Mississippi River is second-longest in North America, 3,730 km. Yellow River is China's second-longest, 3,395 miles. Nile River is Africa's longest, 2,700 km flowing through Egypt and Sudan. Yangtze River is China's longest, 3,900 miles
Rivers collect water through gravity, forming trickles and larger streams. Watershed is an area that drains all water to a single point. River length is measured from mouth to most distant headwater source
Rivers shaped history and provided food, water, and transportation. Climate change poses significant threat to river resources worldwide
Amazon River is world's largest by volume, flowing through Brazil, Peru and Columbia. Orinoco River is fourth largest by discharge volume, with diverse wildlife
River basins are areas where all flowing surface water converges. Rainfall not absorbed or evaporated ends up in nearby rivers