The title of the biggest river depends on the criteria used to measure it: length, volume of water (discharge), or basin area.
By Length:
The Nile River (Africa) is traditionally recognized as the longest river in the world .
The River Nile, which runs through several countries in East and North Africa, is regarded as the longest river on Earth, running nearly 6,700 kilometers from its source in Lake Victoria to its mouth in the Mediterranean.
The Nile has two major tributaries: the White Nile and the Blue Nile. The White Nile is traditionally considered to be the headwaters stream. However, the Blue Nile is the source of most of the water of the Nile downstream, containing 80% of the water and silt.
However, recent measurements suggest the Amazon River (South America) may be slightly longer .
By Water Volume (Discharge):
The Amazon River is the largest river by discharge, carrying more water than the next seven largest rivers combined. Its average discharge is about 209,000 cubic meters per second.
The Amazon River in South America is the largest river by discharge volume of water in the world, and the longest or second-longest river system in the world, a title which is disputed with the Nile
The Amazon represents 20% of the global riverine discharge into oceans
More than one-third of all known species in the world live in the Amazon rainforest. It is the richest tropical forest in the world in terms of biodiversity. In addition to thousands of species of fish, the river supports crabs, algae, and turtles.
By Basin Area:
The Amazon Basin is the largest drainage basin in the world, covering approximately 7 million square kilometers (2.7 million square miles).
The Amazon basin is the part of South America drained by the Amazon River and its tributaries.
It is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela, as well as the territory of French Guiana.
More than 1,400 species of mammals are found in the Amazon
About 1,500 bird species inhabit the Amazon basin
Amazonia is scarcely populated. There are scattered settlements inland, but most of the population lives in a few larger cities on the banks of the Amazon and other major rivers
The most widely spoken languages in the Amazon are Portuguese and Spanish.