Amazon River
The greatest river on Earth by volume, draining half a continent
The Amazon carries more water than the next seven largest rivers combined, discharging into the Atlantic with such force that fresh water can be drawn from the sea more than a hundred miles offshore. It rises as a trickle of glacial meltwater high in the Peruvian Andes, within sight of the Pacific, then turns its back on that ocean and runs the full width of South America. Along the way it gathers more than a thousand tributaries and waters the largest rainforest on the planet.
By the time it crosses into Brazil the river is a brown inland sea, miles wide and dotted with islands that shift with the seasons. Its annual flood pulse can raise water levels by ten meters or more, drowning vast tracts of forest into a flooded landscape where fish swim among the tree canopies. The Rio Negro joins it at Manaus in the famous meeting of the waters, where black and tan currents run side by side for kilometers before mixing. At its mouth the river splits around Marajo Island, an estuary nearly the size of Switzerland, before reaching the Atlantic Ocean.
For the peoples of the basin the river has always been road, larder and calendar — archaeology now suggests its banks once supported far denser populations than the rainforest myth allowed. European explorers gave it its name after reported clashes with woman warriors. Today the Amazon is a front line in the planet's climate: its forests store enormous quantities of carbon, and the health of the river system is bound up with deforestation, gold mining and drought far beyond its banks.