The Amazon River is the largest river in the world by volume of water carried and is responsible for 25% of the fresh water flowing into oceans. It is over 6,400 km long with the largest watershed of any river, containing over 200 tributaries originating from the Andes Mountains across five countries. The massive Amazon River meets the Atlantic Ocean, modifying the color and salinity of the ocean for over 320 km before emptying its waters into the sea.