World Rivers Day

The Kosi River in India and Nepal is known as the “Sorrow of Bihar” because it has changed course dramatically over centuries.

Its shifting channels have displaced villages and altered landscapes. Scientists have recorded at least 12 major course changes in the past 250 years.

The river moves due to heavy monsoons and sediment deposits, creating new paths and unexpectedly flooding areas.

Some researchers compare it to the Mississippi River, which also historically shifted course before levees controlled its movement.

The Puerto Princesa Subterranean River in the Philippines stretches 8.2 km (5 miles) beneath limestone caves.

It flows directly into the sea, making it unique among underground rivers. Visitors can explore parts of it by boat, seeing bats, unique rock formations, and marine life.

It is also a UNESCO World Heritage Site. Some believe it extends even further beyond mapped sections.

Some rivers vanish due to geological activity. The Sambhar Lake River in India disappears into the desert, reappearing elsewhere.

The Lost River in Idaho flows underground for miles before resurfacing. Other rivers, like Mexico’s Atoyac River, have been swallowed by sinkholes.

Climate change and human interference also cause rivers to dry up permanently, as seen with the Colorado River delta, which no longer reaches the sea.

People have discovered bizarre items in rivers, including ancient Viking swords, 14th-century gold coins, and even woolly mammoth bones.

In 2015, a fisherman in the Czech Republic found a 3,000-year-old Bronze Age sword in the Vltava River.

In 2021, archaeologists uncovered a perfectly preserved Roman chariot from the 2nd century AD buried near a river in Croatia.

The Zambezi River in Africa is home to crocodiles, hippos, and bull sharks. Hippos, despite their calm appearance, kill more humans than any other large African animal.

Nile crocodiles are aggressive predators, known for dragging prey underwater. Surprisingly, bull sharks have been found far inland in the river due to their ability to survive in freshwater.

In England, by ancient law, any unmarked swan swimming in the Thames River technically belongs to the British monarchy.

The annual Swan Upping ceremony counts and tags these birds for conservation.

In the U.S., some states have strict laws about fishing in rivers—fishing with your hands (called noodling) is illegal in several states because it threatens fish populations.

The Rio Tinto in Spain runs blood red due to its high iron and sulfur content.

The acidic water supports almost no life, resembling conditions on Mars. NASA even studied the river to understand alien environments. Meanwhile, Canada’s Milk River appears milky due to fine clay particles suspended in the water.

Yes! The Cuyahoga River in Ohio famously caught fire at least 13 times due to pollution.

The most famous fire, in 1969, helped spark the U.S. environmental movement, leading to the Clean Water Act.

The fire was caused by oil slicks and industrial waste floating on the river. Today, the river has recovered significantly.

During World War II, British forces floated fake corpses with false intelligence documents down rivers to trick the Nazis.

One famous case, Operation Mincemeat, involved planting a corpse with misleading papers in a river, fooling German spies into believing an attack would occur in Greece rather than Sicily.

The St. Johns River in Florida flows north most of the time but can reverse due to tides and storms.

It’s one of the few major rivers affected by ocean tides, causing unusual backflow. The Amazon River also experiences a temporary reversal during extreme flooding.