John Snow—not the one from 'Game of Thrones'—determined that contaminated water sickened London

Cholera was called the 'Blue Death'

In the mid-1800s—when John Snow identified cholera in London—the disease was known simply as the "Blue Death." That's because blood would thicken in patients' veins when they were struggling with extreme dehydration. As a result, their skin would turn a blueish hue as their blood was starved of oxygen.

Robert Koch won the Nobel for his tuberculosis work, but he also pioneered cholera research

Koch was one of the first scientists to isolate the bacterium that causes cholera while investigating an outbreak in Egypt in 1883. He went on to advise about rules to control cholera outbreaks, which formed the basis of the disease control approaches and water hygiene techniques still used today.

Cholera went global thanks to global trade

The first cholera pandemic grew from an outbreak in India, in 1817. Scientists suggest it spread from there throughout the continent and onward to Africa, Russia and Europe through the poop of traders.

Paris and Boston were redesigned partly to combat cholera's spread

Georges-Eugène "Baron" Haussmann, who oversaw Paris's redesign in the 1800s, replaced many of the city's narrow streets with wide boulevards. This was done at least in part to bring more air and light into the city to help control cholera. Architect Arthur Gilman redeveloped Boston's Back Bay to similarly combat cholera, among other reasons.

The history of germ theory, which explains that illnesses are caused by microorganisms

For centuries, the miasma theory, which held that illnesses were caused by clouds of "bad air" produced by decaying organic matter, was the accepted explanation for the spread of disease. The development of microscopes and the subsequent technology to isolate bacteria and test disease spread in mice greatly contributed to contagionists overturning miasmatists.

Edward Jenner, the father of vaccinations

The British physician was the first to attempt to inoculate someone from smallpox using its milder cousin, cowpox. His innovations and documentations would prove crucial to the deployment of widespread vaccinations.

The virus was officially described for the first time in 1789

Michael Underwood, an English physician and surgeon, was the first to describe the disorder, noting it caused disability in the lower extremities in children. Large-scale outbreaks of the disease were not observed until the late 19th century.

What was the London Beer Flood of 1814?

On this day 209 years ago, a 15-foot-high wave of beer roared through the streets of an impoverished London neighborhood, killing eight people. Read this beer historian's account of the tragedy to learn more. The beer had burst from the nearby...

Wastewater testing has detected genetic evidence of polio, triggering vaccine boosters

Sampling of wastewater in London in 2022 detected fragments of polio virus, suggesting a vaccine-derived version of polio may be circulating. No one became ill, but the finding did trigger calls for a renewed booster inoculation campaign.

The unexpected origin story of the snow globe

In 1900, a Vienna tradesman named Erwin Perzy I was attempting to invent an inexpensive way to improve light amplification in hospital operating rooms. After experimenting with a glass globe filled with water, the idea for the snow globe struck. Industrious as well as inventive, Perzy eventually turned his idea into a successful business. Read the full article to learn how the invention grew to become recognized globally.

How a polluted New York City waterway created extremophiles hungry for 'black mayonnaise'

In the 19th century, coal processing plants, oil refineries, a tannery, and other industries lining the Gowanus Canal contaminated its waters with coal tar, sewage, and other pollutants, forming the toxic sludge. Samples taken from the site before clean-up efforts revealed over 450 species of microbes with metabolisms adapted to break down these contaminants.

How Monet’s paintings changed the way we see London

Between 1899 and 1901, legendary French Impressionist painter Claude Monet produced over 100 paintings of London consistently shrouded in fog. Art historians claim this series left a permanent mark on how we perceive the capital city, inevitably layered in obscuring and dramatic mist. See some of the paintings and read more here.

How LA brought water to its booming population

By the turn of the 20th century, Los Angeles had grown from a dusty, crime-ridden pueblo into a thriving metropolis. The only problem was that it was growing too fast. Here's the story of how the booming town created a massive water infrastructure to redirect area rivers to its residents.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Disney World is largely mosquito-free, thanks to civil engineer Joe Potter

As a former governor of the mosquito-prone Panama Canal zone, Potter understood the danger of standing water. At Disney, Potter built ditches to reduce moisture, designed buildings to channel water away, and more. His efforts help visitors avoid bites, adding to the perceived magic of the magical kingdom.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Maps of murder across medieval England

These interactive maps show the sites of murders across York, Oxford, and London during the 14th Century. Explore the data by clicking site pins or experimenting with map filters, including crime scene type and murder weapon. Each pin includes a blurb on what researchers concluded about the attack, such as how a fight between the London fishmonger and skinner guilds during August 1340 ultimately left one man dead.

Charles Darwin studied goose bumps by scaring zoo animals in London with a stuffed snake

Read the famous naturalist’s work from the late 1800s, detailing how he sought to draw comparisons between how animals and humans respond to fear. As part of that work, he exposed monkeys and a peccary to a stuffed snake and noted the animals’ hair-raising fear response.

Dickens' earliest pieces were under the pseudonym 'Boz'

Dickens began working as a journalist in 1829, publishing his portraits of modern life under a pseudonym. In 1834, he used the pen name "Boz," a reference to his brother's childhood nickname, and eventually published a collection of his stories called "Sketches by Boz." By the 1840s, he'd ditched the pseudonym, enjoying his rarefied literary celebrity.

Validation of the greenhouse effect may have been misattributed

Although Irish physicist John Tyndall showed in 1859 that water vapor and carbon dioxide could absorb and radiate infrared radiation, experiments by American scientist Eunice Foote three years earlier identified the same phenomenon for light in general. Historically overshadowed, her work was rediscovered by female historians over a century later.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Reflections from Ben Giles, history's greatest stain remover

Starting out as a freelance window cleaner, the British cleaning legend started taking on jobs cleaning out people's garages and shacks. He soon realized people would pay top-dollar to have their worst messes cleaned up by someone else.

How a sick George Orwell finished '1984'

The writer worked on the novel while living in a remote cottage in Scotland. While he was there, he was in a boating accident that sent him overboard, eventually leading to a fatal bout of tuberculosis. Orwell finished the novel (and massive revisions) while trying to recover. He died in 1950, at 46.

View a map of countries with the safest and most dangerous drinking water

More than a quarter of the world's population lives in water-stressed countries, and a similar number use contaminated drinking water sources, which can lead to widespread disease, according to the World Health Organization. The Environmental Performance Index shows which countries have safe drinking water.

The medieval influencer who convinced people to drink tea

This article explains how the world shifted from mostly eating tea, whether as leaves to be chewed or caffeinated soup to be slurped, to drinking it. Lu Yu's first exposure to tea in the 700s didn't go so well, with him reviewing the concoction as...

Stephen Hawking's early rowing days shaped the bold persona for which he became known

Before gaining fame as a physicist, Hawking was a coxswain at Oxford, where the sport helped him find his social footing and develop leadership skills, even as his motor neuron disease began to emerge.

Wastewater from geothermal power plants helps melt sidewalk snow in Iceland

Located on the Mid-Atlantic ridge, where the North American and Eurasian tectonic plates move apart, the nation saw geothermal power meet more than 90% of its heating demand in 2024. After the hot water produced by these plants is used to heat homes and businesses, it is transferred through small pipes beneath Reykjavík's sidewalks.

Joseph Pulitzer mainstreamed 'yellow journalism'

One way Joseph Pulitzer revolutionized the newspaper industry by developing an approach to reporting that relied on sensationalism and could be a little loose with the facts. Pulitzer and rival William Randolph Hearst pushed that sensationalism to the next level in their competition to attract readers.

How the most famous Ebola book, The Hot Zone, which sold 3.5 million copies and was translated into 30 languages, got aspects of the disease so wrong.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

In 1915, workers recovered a submarine-like vessel from the Chicago River, prompting fears of German espionage

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

See 33 images that became central to huge scandals, including a young Charles and Camilla, Michael Jackson's baby on a hotel balcony, and Hugh Grant's mugshot.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

The Brothers Grimm were lawyers before they were storytellers, and became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

The identity of the Tank Man in the iconic photo from the 1989 Tiananmen Square protests remains unknown and was possibly killed.

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Watch a 1934 short film starring jazz legend Cab Calloway, a major figure in the Harlem Renaissance's music scene