The Amazon River (Portuguese: Rio Amazonas; Spanish: Río Amazonas) of South America is the largest river in the world by volume, with a total river flow greater than the next eight largest rivers combined. The Amazon, which has the largest drainage basin in the world, accounts for approximately one fifth of the world's total river flow. During the wet season parts of the Amazon exceed 120 miles (190 km) in width. Because of its vast dimensions, it is sometimes called The River Sea. At no point is the Amazon crossed by bridges. This is not because of its huge dimensions; in fact, for most of its length, the Amazon's width is well within the capability of modern engineers to bridge. However, the bulk of the river flows through tropical rainforest, where there are few roads and even fewer cities, so there is no need for crossings.
While the Amazon is the largest river in the world by most measures, the current consensus within the geographic community holds that the Amazon is the second longest river, just slightly shorter than the Nile.
The Amazon basin, the largest drainage basin in the world, covers about 40 percent of South America, an area of approximately 6,915,000 square kilometres (2,670,000 sq mi). It gathers its waters from 5 degrees north latitude to 20 degrees south latitude. Its most remote sources are found on the inter-Andean plateau, just a short distance from the Pacific Ocean.
The area covered by the water of the Amazon River and its tributaries more than triples over the course of a year. In an average dry season 110,000 square kilometres (42,000 sq mi) of land are water-covered, while in the wet season the flooded area of the Amazon Basin rises to 350,000 square kilometres (135,000 sq mi).
The quantity of water released by the Amazon to the Atlantic Ocean is enormous: up to 300,000 m³ per second in the rainy season. The Amazon is responsible for a fifth of the total volume of fresh water entering the oceans worldwide. Offshore of the mouth of the Amazon, potable water can be drawn from the ocean while still out of sight of the coastline, and the salinity of the ocean is notably lower five hundred kilometres out to sea.
