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The Yenisei River is the world's fifth-longest river system and the largest draining into the Arctic Ocean.

The world’s sixth largest river in terms of discharge, the Yenisey runs from south to north across the great expanse of central Siberia. It traverses a vast region of strikingly varied landscapes where ancient peoples and customs as well as an enormous economic infrastructure are found.

About half of the Yenisey’s water comes from snow, a little more than one-third from rainwater, and the remainder from groundwater. For the greater part of the system, the eastern Siberian hydrologic regime prevails: violent spring floods are followed first by a rapid fall of levels, then by a slower fall, with summer and autumn rain floods punctuating the sequence; in winter the runoff is reduced sharply, but levels remain high as ice jams are formed. In terms of runoff, the Yenisey is the largest river in Russia, with about 150 cubic miles (620 cubic kilometres) annually.

Hunting, fishing, the breeding of reindeer, and fur farming are the traditional occupations of the more northerly peoples, and there is some mining of coal and nonferrous ores (copper, nickel) around Norilsk. Since the 1950s, power stations have been built on the Angara at Irkutsk, Bratsk, and Ust-Ilimsk and on the upper and middle Yenisey at Krasnoyarsk and Sayan, with a combined total generating capacity exceeding 25 million kilowatts. Another station on the Angara, at Boguchany, was completed in the late 1980s. Lumber is the main cargo. Some of the cargo goes upstream to Krasnoyarsk, but the downstream traffic carries bread, coal, petroleum products, and machinery, as well as lumber.

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The Yangtze or Yangzi is the longest river in Asia, the third-longest in the world and the longest in the world to flow entirely within one country. Its drainage basin comprises one-fifth of the land area of China, and is home to nearly one-third of the country's population.

The name Yangtze—derived from the name of the ancient fiefdom of Yang—has been applied to the river mainly by those in the West. Chang Jiang (“Long River”) is the name used in China, although it also is called Da Jiang (“Great River”) or, simply, Jiang (“[The] River”). The Yangtze is the most important river of China. It is the country’s principal waterway, and its basin is China’s great granary and contains nearly one-third of the national population.

In its upper reaches the Yangtze River drains across the Plateau of Tibet, which is still uplifting as the Indian and Eurasian tectonic plates collide. The bedrock comprises an assemblage of marine sedimentary, igneous, and metamorphic rocks. Within intermontane basins, thick deposits of sediments of Cenozoic age—i.e., less than about 65 million years old—overlie the bedrock. The Yangtze descends abruptly from the Tibetan Plateau to flow across deeply eroded mountain plateaus consisting of Paleozoic and Mesozoic rocks roughly 350 to 150 million years old. In its lower reaches, the Yangtze River flows across basin fills of Cenozoic material that is about 65 to 25 million years old. These are the result of fluvial sedimentation as the Yangtze has migrated across its lower basin throughout its Cenozoic history.

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The Mississippi River runs through or along 10 states, from Minnesota to Louisiana, and is used to define portions of these states borders, with Wisconsin, Illinois, Kentucky, Tennessee, and Mississippi along the east side of the river, and Iowa, Missouri, and Arkansas along its west side.

Although the Mississippi can be ranked as the fourth longest river in the world by adding the length of the Missouri-Jefferson (Red Rock) system to the Mississippi downstream of the Missouri-Mississippi confluence—for a combined length of 3,710 miles (5,971 km)—the 2,340-mile length of the Mississippi proper is comfortably exceeded by 19 other rivers. In volume of discharge, however, the Mississippi’s rate of roughly 600,000 cubic feet (17,000 cubic metres) per second is the largest in North America and the eighth greatest in the world.

As the central river artery of a highly industrialized nation, the Mississippi River has become one of the busiest commercial waterways in the world, and, as the unruly neighbour of some of the continent’s richest farmland, it has been subjected to a remarkable degree of human control and modification. Furthermore, the river’s unique contribution to the history and literature of the United States has woven it like a bright thread through the folklore and national consciousness of North America, linking the names of two U.S. presidents—Abraham Lincoln and Ulysses S. Grant—with that of the celebrated author Mark Twain.

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The Amazon River is the second longest river in the world, slightly shorter than the Nile River (4,258 miles or 6,853 km), although some experts contend that the two rivers are so close in length (since measuring methods vary and there is still some dispute over their true sources) that it is difficult to say which river is actually longer. 

The modern Amazon and its tributaries occupy a vast system of drowned valleys that have been filled with alluvium. With the rise in sea level that followed the melting of the Pleistocene glaciers, the steep-sided canyons that had been eroded into the Pliocene surface during the period of lower sea levels were gradually flooded. In the upper part of the basin—in eastern Colombia, Ecuador, Peru, and Bolivia—more-recent outwash from the Andes has covered many of the older surfaces.

There are more than 1,000 tributaries of the Amazon that flow into it from the Guiana Highlands, the Brazilian Highlands, and the Andes. Six of these tributaries—the Japurá (Caquetá in Colombia), Juruá, Madeira, Negro, Purus, and Xingu rivers—are each more than 1,000 miles (1,600 km) long; the Madeira River exceeds 2,000 miles (3,200 km) from source to mouth. The largest oceangoing ships can ascend the river 1,000 miles to the city of Manaus, Brazil, while lesser freight and passenger vessels can reach Iquitos, Peru, 1,300 miles (2,090 km) farther upstream, at any time of year.

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Nile River, the longest river in the world, called the father of African rivers. It rises south of the Equator and flows northward through northeastern Africa to drain into the Mediterranean Sea.

The name Nile is derived from the Greek Neilos (Latin: Nilus), which probably originated from the Semitic root na?al, meaning a valley or a river valley and hence, by an extension of the meaning, a river.

The availability of water from the Nile throughout the year, combined with the area’s high temperatures, makes possible intensive cultivation along its banks. Even in some of the regions in which the average rainfall is sufficient for cultivation, marked annual variations in precipitation often make cultivation without irrigation risky.

The Nile River is also a vital waterway for transport, especially at times when motor transport is not feasible—e.g., during the flood season. Improvements in air, rail, and highway facilities beginning in the 20th century, however, greatly reduced dependency on the waterway.

Credit : Britannica 

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