EARTH’S ARTERIES

Which is the longest river in the world? Learn 10 cool facts about rivers

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Rivers are the arteries of our planet. By connecting lands, lakes, and the sea, they enable the circulation of nutrients, sediments, and living beings. And despite holding a very small percentage of the water on Earth, they sustain most of its life!

Here are 10 intriguing facts about rivers from across the world.

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Over millions of years, rivers have carved some of the most awe-inspiring landscapes on Earth. From the Grand Canyon at the Colorado River to the Three Gorges at the Yangtze River, waterways are powerful sculptors, shaping valleys, canyons, and deltas by eroding rocks at some points and depositing the resulting sediments further downstream. Without rivers, we would live on a very different planet!

Image: Xuan Nguyen

Throughout history, rivers have served as vital arteries for human civilization. The earliest human settlements first sprouted along river banks - like the Tigris and Euphrates, the Nile, the Indus, and the Yellow River - drawn by abundant food, fertile soil, natural resources, and access to water for drinking and agriculture. Currently, freshwater fisheries sustain up to 550 million people! Rivers also function as transportation routes, and borders between countries.

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Rivers are teeming with life, hosting a diverse array of plants, animals, and microorganisms. In fact, they are some of the most diverse ecosystems on the planet, sustaining more fish species than the sea! Rivers also serve as corridors for land-based wildlife, keeping animal populations healthy and helping preserve biodiversity.

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Rivers play a crucial role in the water cycle, transporting vast quantities of water from land to sea. Every year, 38 trillion cubic meters of river water flow into the oceans! Most of this is actually rainwater, created through the evaporation of ocean water. Along their way, they also replenish groundwater reserves, nourishing ecosystems and sustaining human communities during dry spells.

Image: Philipp Potocnik

Healthy rivers also act as natural filters, purifying water along their course and removing pollutants. Wetlands, floodplains, and riparian zones help trap sediment and absorb excess nutrients, safeguarding downstream water quality. This is why it’s so important to fight pollution and preserve rivers’ capacity for regeneration. When this filter fails, problems go downstream and end up in the ocean, silently accumulating and causing serious ecological imbalances.

Image: Cédric Dhaenens

Rivers are a potent source of renewable energy, driving hydroelectric dams that generate electricity. Nowadays, dams store one-sixth of the water flowing in rivers, and hydropower accounts for 16% of the world’s electricity. However, though they are considered a greener form of energy, if they are not adequately planned hydroelectric dams can come at great cost to river ecosystems and communities.

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Rivers have long been cultural and spiritual symbols, revered by indigenous peoples and civilizations around the world. They feature prominently in myths, rituals, and religious beliefs, embodying concepts of life, renewal, and the divine. Rivers also create identity - there are at least 17 countries that are named after rivers, including India, Nigeria, Congo, and Belize! Moreover, they are hotspots for recreation, providing havens for birdwatching, camping, and hiking, drawing millions of visitors each year to their shores.

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Despite their importance, rivers face a myriad of threats, including pollution, habitat destruction, and overexploitation. It is currently estimated that at least 10,000 to 20,000 freshwater species have gone extinct or are on the brink of extinction. A staggering 37% of the world’s freshwater fish species are seriously threatened. Climate change exacerbates these challenges, leading to altered flow regimes, increased flooding, and habitat loss.

Image: Jordi Orts Segalés

Stretching over 4,130 miles, the Nile is not just the longest river in Africa but also the entire world. Originating from Lake Victoria in Uganda, it flows through eleven countries, including Egypt, where it empties into the Mediterranean Sea. From ancient times, the Egyptian and Sudanese kingdoms have heavily depended on the river and its annual cycles of flooding, and to this day most of the population and cities of Egypt lie along the valley of the Nile.

Image: Nareeta Martin

The Amazon River in South America carries more water than any other river, accounting for approximately 20% of the total freshwater discharge into the oceans - it is estimated that every second, 84 olympic-sized pools are discharged into the sea from its mouth! It also has a massive basin, covering over 2.7 million square miles, most of which is part of the Amazon rainforest.

Bad picks from the forest

Deadly fungi: 10 poisonous mushrooms you don't want to mess with

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Going mushroom hunting in the woods during the fall or spring can be a fun and rewarding activity. However, it is important to first learn how to differentiate between edible and poisonous fungi. Depending on the species, mushrooms can pose different dangers. Some may cause minor indigestion, while others can be fatal. In this article, we’ll unmask 10 dangerous mushrooms you should stay away from. Do you know which species is responsible for the most mushroom-related fatalities each year?

Image: Andriy Nestruiev

When we think of mushrooms, the first image that often comes to mind is a cute little red cap covered in white dots. Amanita muscaria is the classic mushroom found in children's books and is likely the most photographed mushroom in the world. But did you know it can be dangerous?

This mushroom’s colloquial name, fly agaric, probably derives from its traditional use as a fly killer. It has also been used throughout history in religious rites for its hallucinogenic properties. However, the presence of several toxins can produce other effects as well, including nausea, vomiting, and diarrhea. Although it is not the most poisonous of all mushrooms, it’s best not to be seduced by its charming appearance—stay away from it.

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Cortinarius orellanus is a medium-sized mushroom with a cylindrical yellowish stem, an orange-brown cap, saffron-colored gills, and yellowish flesh. Commonly known as the fool’s webcap, it is native to Europe and is typically found in mountain forests. It prefers moist, organic-rich soils and is most prevalent during the summer and fall months.

The fool’s webcap is one of the most poisonous mushrooms known to exist. It contains orellanin, a nephrotoxic compound that can cause severe kidney damage in humans. Symptoms of poisoning—including lower back pain, nausea, vomiting, and diarrhea—can take several days to appear, making diagnosis and treatment especially difficult.

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This species is considered one of the few toxic members of the Boletus genus. In the areas where it grows—warmer regions of Europe—it is feared for its poisonous effects, which appear shortly after ingestion. Although caution is warranted, it is not a deadly mushroom; however, it can cause dehydration, diarrhea, nausea, and severe abdominal pain.

Despite bearing some resemblance to edible mushrooms, its size often gives it away. Satan’s bolete can reach up to 20 inches in width, and it is not uncommon to find specimens weighing around 4.5 pounds. Its cap is beige, it has a bulbous red stem, its flesh is light yellow and turns blue when cut, and it emits a notably unpleasant odor.

Image: Hans

Psilocybe semilanceata, commonly known as the liberty cap, is a mushroom known for its psychotropic effects. It grows mainly in humid and temperate areas of the Northern Hemisphere, particularly in Europe. It has a distinctive nipple-shaped cap, and its color ranges from whitish when young to brown as it matures. The mushroom has a bitter taste.

Although the liberty cap is considered to have low toxicity, its ingestion can produce a range of effects, including altered perception of space and time. It may also cause temporary paranoia, with effects typically lasting between 3 and 6 hours. For this reason, its consumption is not recommended outside of a controlled environment.

Image: Erik Karits

Eating even a single piece of Amanita virosa can cause irreversible liver damage, and you should be especially careful because it can be easily mistaken for edible white-capped species.

In the eastern United States, the destroying angel appears from early summer to early autumn. It has a white cap that is initially ovoid and later flattens with age. The stalk is slender and covered with fine hairs, and it features a membranous ring. Despite its pleasant smell and reportedly good taste, this mushroom is extremely poisonous—ingesting it can result in death.

Image: ChristianSW, CC0, via Wikimedia Commons

The false morel can be found in spring in coniferous forests. Its cap is brain-like, with intricate wrinkles and folds, and its color ranges from light brown to reddish brown depending on humidity.

Despite its scientific name—Gyromitra esculenta ("esculenta" meaning "edible")—the false morel is highly toxic unless properly prepared. In some individuals, it can be dangerous even after cooking; its toxins are volatile, and poisoning can occur by inhaling the fumes released during boiling. Nevertheless, the false morel remains a popular mushroom in some European countries, such as Finland, where it is used in certain traditional dishes. Would you dare to try it?

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Lepiota brunneoincarnata may be tiny in size, but it is unquestionably deadly. It’s important to be able to recognize this mushroom and exercise caution when encountering it in the wild. The good news is that its appearance differs significantly from most edible species, making it less likely to be confused with them.

Commonly known as the deadly dapperling, this mushroom is found throughout Europe and parts of Asia. It typically appears during the summer and autumn months in meadows, parks, gardens, shrublands, and along roadsides. It contains a toxin called amatoxin, which is absorbed through the digestive tract and can cause symptoms such as abdominal pain, gastroenteritis, diarrhea, and vomiting. If not treated promptly, it can lead to death within a week.

Image: Vladimir Srajber

Galerina marginata, known colloquially as autumn skullcap, is found in coniferous forests across North America, Europe, Asia, Japan, and Australia. Although it can appear at various times of the year, it is most commonly found in autumn. It has a soft brownish color, and its cap surface is often slimy with a greasy appearance.

Like the deadly dapperling, the autumn skullcap contains amatoxins, which interfere with essential cellular functions. The first symptoms of poisoning appear 6 to 24 hours after ingestion. It can cause renal failure and eventually death if not treated within the first four days.

Image: Hans

Entoloma sinuatum is responsible for numerous cases of poisoning, as it can be mistaken for several edible species. At first glance, the body of the livid pinkgill looks like a classic field mushroom—its cap often displays a creamy light gray color. It typically grows in clay and limestone-rich soils, especially in beech and oak forests across Europe and parts of North America.

Although it does not have an unpleasant taste, you shouldn’t eat it. It can cause severe gastrointestinal disorders, including persistent diarrhea and vomiting, which may last for several days, and in some cases, up to two weeks.

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The death cap (Amanita phalloides) accounts for the vast majority of mushroom poisoning deaths worldwide—hence its name. Consuming less than 2 ounces of this mushroom is enough to be fatal; an even smaller dose can kill a child and cause severe poisoning in adults.

Native to the United Kingdom and parts of Ireland, the death cap has rapidly spread over the past century to Australia and North America. It can grow up to 6 inches tall and has a domed cap sometimes tinged yellow or green, along with a white stem, which makes it difficult to distinguish from some edible mushrooms. Even its spores are poisonous. Therefore, if you have handled a death cap, avoid touching your mouth and always wash your hands thoroughly before eating.