Amazon River

   The Amazon River in South America is the second longest river in the world and is by far the largest by water flow with an average discharge greater than the next seven largest rivers combined (not including Madeira and Rio Negro, which are tributaries of the Amazon). The Amazon, which has the largest drainage basin in the world, about 7,050,000 square kilometers (2,720,000 sq mi), accounts for approximately one-fifth of the world's total river flow. In fact, the river becomes biggest in the world even just entering Brazil, at only 1/5 of its final discharge into the Atlantic.

   In its upper stretches, above the confluence of the Rio Negro, the Amazon is called Solimões in Brazil; however, in Peru, Colombia and Ecuador, as well as the rest of the Spanish-speaking world, the river is generally called the Amazon downstream from the confluence of the Marañón and Ucayali rivers in Peru. The Ucayali-Apurímac river system is considered the main source of the Amazon, with as its main headstream the Carhuasanta glacial stream flowing off the Nevado Mismi Mountain.

   The width of the Amazon is between 1.6 and 10 kilometers (1.0 and 6.2 mi) at low stage but expands during the wet season to 48 kilometers (30 mi) or more. The river enters the Atlantic Ocean in a broad estuary about 240 kilometers (150 mi) wide. The mouth of the main stem is 80 kilometers (50 mi). Because of its vast dimensions, it is sometimes called The River Sea. The first bridge in the Amazon River system (over the Rio Negro) opened on 10 October 2010 near Manaus, Brazil.