Its namesake river is by far the largest on the earth, rivaling the Nile for the distinction of longest. Most of the basin is covered with the world's most extensive tropical rain forest, which, despite logging and development, continues to hold wilderness of astounding biological richness. In fact, it was only in 2005 that scientists discovered evidence that our current climate change situation was already affecting the Amazon. Since then, several studies have shown that the rain forest is becoming less fertile due to increased temperatures.
The Xingu River flows through four Brazilian states before emptying into the Atlantic Ocean. It is the largest tributary of the Amazon River and second-largest in Brazil after the Tapajos River.
The source of the Xingu is in the Andes Mountains in northern Peru, but most of its course is in remote tropical rain forest in four different countries: Brazil, Peru, Venezuela, and Colombia. Only about 15% of the river's length is within Brazil.
It is here in the Amazonian rainforest where you will find the Xingu River. The Xingu is so large that it contains many small rivers that are fed by melting snow from the Andes mountain range.
The Xingu River flows for more than 1,000 miles through a series of low hills and flat surfaces before reaching the Atlantic Ocean.
4,000 kilometers While there is considerable disagreement over its length, it is widely assumed to be at least 4,000 miles (6,400 km) long, making it the world's second longest river after the Nile River in Africa. The Amazon is also well-known for the jungle that grows along its shores.
The Amazonian rainforest has been called the "lungs of the planet" because it absorbs carbon dioxide from the atmosphere and releases much of it back into it when it burns. The forest also provides water to millions of people who would otherwise have no access to it. It is also a major source of minerals such as iron, zinc, and copper. This shows how important it is for our planet that this unique environment be protected.
When the first Europeans arrived in South America, they found an extremely diverse culture with many different kinds of animals and plants. The new invaders quickly took advantage of this fact by hunting most of them down for food or money. By 1650, almost all the large mammals had been killed, leaving just a few native species alive today. Today, one of the only wild places where you can find big animals is in zoos, so this story will probably not be repeated here. However, there are many other interesting species in South America that have been saved from extinction. For example, three of the four living species of condor are found in Brazil. There are also several types of monkeys, parrots, and anteaters in South America.
Although the Amazon is the world's greatest river in terms of volume, experts believe it is somewhat shorter than Africa's Nile. The Amazon is 4,225 miles (6,800 kilometers) long, according to the team's unpublished data. The Nile is 4,160 km long (6,695 kilometers) when including its tributaries.
The Amazonian and African rivers have very different geological origins. The Amazon comes from glaciers in the Andes mountains, while the Nile flows from the hot volcanic rocks of Africa's Great Rift Valley.
However, they both start in highlands and then flow into the lowlands. This pattern is common for most great rivers on Earth.
Great rivers are often used as trade routes since they offer convenient ways to transport goods over large distances. For example, the Amazon has served as a route for traders traveling between South America and Europe since at least 1492. At that time, Portuguese explorers arrived at its estuary with spices and silk from Asia and gold and silver from South America; this exchange continued after Brazil became a country in 1822.
Many large cities are located along great rivers because of their economic importance. Examples include Cairo, Egypt and Kampala, Uganda.
These two examples show that it is not only natural resources that great rivers can provide for their civilizations. They can also be useful tools for transportation and communication.
In reality, while the Amazon is considered by some to be the world's longest river, it is "quite a child among rivers," according to Hoorn. According to Figueiredo, the entire history of the fluvial drainage system that finally formed the transcontinental Amazon River that we know today is older than 11 million years. The Mississippi-Missouri-Illinois system was already long established by then.
The Amazon itself is a relatively young river system. It began forming about 12 million years ago when the sea covered much of South America and cut off the flow of water into the Atlantic Ocean. As the land dried out, large areas of what is now Brazil were transformed from forest into savannah or caatinga.
With no trees growing on the ground to absorb rainfall, all of the water ran off into small lakes or droughts. Over time, these small depressions filled in with sediment creating new lands that are now part of the great Brazilian shield volcano formation. With no longer any flow of water into the ocean, the Amazon River System began to form.
At first, only small streamlets called córreos flowed into the nascent river. As the climate changed and more rain fell as snow rather than saltwater, more rivers joined the Amazônia in a process known as "flowing down" from higher up in the mountains.
The White Nile is the longest of the two, but the Blue Nile provides more water to the river. The Amazon River is the world's second longest river, measuring around 3,980 miles (6,400 km).
The image above shows just a part of what's left of the mighty Amur River after it flows through Russia and China. In its final stretch before entering Asia, the Amur drops down nearly 300 meters (1,000 feet) over a distance of 80 kilometers (50 miles).
The Amur used to be the largest river in Europe until the Danube surpassed it in size about 12,000 years ago. Early humans used to live by the Amur River as far back as 500,000 years ago! But due to development, most of the Amur has been dammed for irrigation or else disappeared under streets and highways. Only about one-third of it remains undammed.
The Amur River flows into the Pacific Ocean near Vladivostok, Russia.
The 14-day journey by Brazilian scientists increased the Amazon's length by around 176 miles (284 kilometers), making it 65 miles (105 kilometers) longer than the Nile. They based their calculation on measurements taken between 1972 and 2004.
The Amazon is also considerably wider than the Nile. One team of researchers estimated that it has a width of 690 miles (1090 kilometers), while the other team calculated a width of 730 miles (1140 kilometers). Either way, it's more than twice as wide as the Nile.
These estimates should not be considered exact figures because there are many uncertainties with hydrology data from beyond the European frontier. However, they do provide a reasonable basis for comparison.
It is difficult to compare the size of these two important rivers because they have such different characteristics. The Amazon is a huge river, while the Nile is relatively small. But they both have vast geographic ranges with extensive downstream flows that contain many large islands.
Their differences in size can be attributed to several factors. The Amazon has more massive tributaries than the Nile, which reduces its overall magnitude. The Congo River, for example, is nearly three times as long as the Nile but only half as wide.