Mapped: The Drainage Basins of the World's Longest Rivers
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Mapped: The Drainage Basins of the World’s Longest Rivers



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Drainage basins of the world's longest rivers

Drainage Basins of the World’s Longest Rivers

Most of the earth’s surface is covered in water, but less than 1% of it is the fresh water that makes up the rivers and lakes we’re familiar with.

The water we encounter in life is moving through the stages of the water cycle. And even though rivers make up a tiny portion of all fresh water, they’re still one of the most visible parts of that cycle, especially for the billions of people who live in cities and towns built alongside them.

Of course, rivers don’t just appear out of nowhere. They’re the end result of water’s land-based journey–the product of many compounding inflows collected within a drainage basin.

The map above, from Reddit user r/CountZapolai, illustrates how massive the drainage basins can be for the world’s longest rivers.

What is a Drainage Basin?

A river’s drainage basin is defined as the area of land where precipitation collects and drains off, feeding the flow of rivers and their tributaries. Simply put, this is the process of water draining from higher points of land to lower laying areas–as demonstrated by the animation below.

drainage basins animation

In the case the world’s longest rivers, these drainage basins can span across entire continents and cross many international borders.

Fueling the World’s Longest Rivers

The longer a river system gets, the more terrain it passes through. It comes as no surprise then that the longest rivers are supported by immense drainage basins.

Here are the world’s top 10 longest rivers, and the size of their respective basins:

RankRiver systemLength in miles (km)Drainage area in miles² (km²)OutflowCountries in basin
Atlantic Ocean🇧🇷🇵🇪🇧🇴🇨🇴🇪🇨🇻🇪🇬🇾
East China Sea🇨🇳
Gulf of Mexico🇺🇸🇨🇦
Kara Sea🇷🇺🇲🇳
6Huang He (Yellow River)3,395
Bohai Sea🇨🇳
Gulf of Ob🇷🇺🇰🇿🇨🇳🇲🇳
8Río de la Plata3,030
Río de la Plata🇧🇷🇦🇷🇵🇾🇧🇴🇺🇾
Atlantic Ocean🇨🇩🇨🇫🇦🇴🇨🇩🇹🇿🇨🇲🇿🇲🇧🇮🇷🇼
Sea of Okhotsk🇷🇺🇨🇳🇲🇳

Note: There is debate about the actual length of certain river systems. See a more comprehensive range of estimates here.

These 10 longest rivers alone are fed by a land area equivalent to the size of Africa.

Of those, the Amazon Basin is the largest in the world by far, covering one-third of the South American continent.

River Drainage Basins and Humanity

The fact that huge population centers sit at the terminuses of many of these key rivers is a testament to how important watersheds are to our survival. Only 10% of the global population lives further than six miles away from a surface freshwater body, and more often than not, that fresh water comes in the form of a river.

Noting where rivers begin their journey is also important as well. In the case of Tibet, many of the world’s longest rivers are fed by drainage basins that begin in the region. In fact, six of Asia’s major rivers begin on the Tibetan Plateau, meeting the basic needs of billions of people.

By illustrating the world’s longest rivers and their drainage basins, maps like this one help put into perspective the breathtaking complexity of Earth’s hydrological cycle.

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Visualizing the Odds of Dying from Various Accidents

This infographic shows you the odds of dying from a variety of accidents, including car crashes, bee stings, and more.



Infographic: The Odds of Dying from Various Accidents

Fatal accidents account for a significant number of deaths in the U.S. every year. For example, nearly 43,000 Americans died in traffic accidents in 2021.

Without the right context, however, it can be difficult to properly interpret these figures.

To help you understand your chances, we’ve compiled data from the National Safety Council, and visualized the lifetime odds of dying from various accidents.

Data and Methodology

The lifetime odds presented in this graphic were estimated by dividing the one-year odds of dying by the life expectancy of a person born in 2020 (77 years).

Additionally, these numbers are based on data from the U.S., and likely differ in other countries.

Type of AccidentLifetime odds of dying (1 in #)
Motor vehicle accident101
Complications of medical and surgical care798
Alcohol poisoning1,606
Accidental building fire1,825
Choking on food2,745
Drowning in swimming pool5,782
Accidental firearm discharge7,998
Airplane accident11,756
Bee or wasp sting57,825
Dog attack69,016
Lightning strike138,849

For comparison’s sake, the odds of winning the Powerball jackpot are 1 in 292,000,000. In other words, you are 4000x more likely to die by a lightning strike over your lifetime than to win the Powerball lottery.

Continue reading below for further context on some of these accidents.

Motor Vehicle Accidents

Motor vehicle accidents are a leading cause of accidental deaths in the U.S., with a 1 in 101 chance of dying. This is quite a common way of dying, especially when compared to something like bee stings (1 in 57,825).

Unfortunately, a major cause of vehicle deaths is impaired driving. The CDC reports that 32 Americans are killed every day in crashes involving alcohol, which equates to one death every 45 minutes.

For further context, consider this: 30% of all traffic-related deaths in 2020 involved alcohol-impaired drivers.


The odds of drowning in a swimming pool (1 in 5,782) are significantly higher than those of drowning in general (1 in 10,386). According to the CDC, there are 4,000 fatal drownings every year, which works out to 11 deaths per day.

Drowning also happens to be a leading cause of death for children. It is the leading cause for kids aged 1-4, and second highest cause for kids aged 5-14.

A rather surprising fact about drowning is that 80% of fatalities are male. This has been attributed to higher rates of alcohol use and risk-taking behaviors.

Accidental Firearm Discharge

Lastly, let’s look at accidental firearm deaths, which have lifetime odds of 1 in 7,998. That’s higher than the odds of drowning (general), as well as dying in an airplane accident.

This shouldn’t come as a major surprise, since the U.S. has the highest rates of gun ownership in the world. More importantly, these odds highlight the importance of properly securing one’s firearms, as well as learning safe handling practices.

As a percentage of total gun-related deaths (45,222 in 2020), accidental shootings represent a tiny 1%. The two leading causes are suicide (54%) and homicide (43%).

Interested in learning more about death? Revisit one of our most popular posts of all time: Visualizing the History of Pandemics.

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