Rivers of the World

Rivers — linear water bodies draining watersheds into oceans, lakes, or other rivers — have been the cradles of every major civilization (Nile → Egypt; Tigris-Euphrates → Mesopotamia; Indus → Indus Valley civilization; Yangtze/Yellow River → China; Mississippi → Native American cultures; Rhine/Danube → Roman Empire boundary). Rivers provide fresh water, transport, food (fish), fertile floodplain soil (annual flood deposits), hydroelectric power, and natural boundaries. World's great rivers: the Nile (6,650 km, longest); the Amazon (6,400 km, greatest discharge by far — 20% of world's freshwater); the Yangtze (6,300 km, longest in Asia, Three Gorges Dam); the Mississippi-Missouri (6,275 km, drains 40% of North America, the highway of the American interior); the Congo (deepest river, 220m in places, drains the world's second-largest rainforest); the Ganges (most sacred river in Hinduism, 400 million people dependent on it). Most major rivers are now heavily modified: 60% of the world's large river systems have been fragmented by dams. The Three Gorges Dam (Yangtze, completed 2012) is the world's largest power station, producing 22,500 MW, but displaced 1.3 million people and destroyed river dolphin habitat.