Volcanoes in the 1340s likely helped trigger the Black Death

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.

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.

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.

The bubonic plague spread in three waves over 600 years

The Black Death refers to the first wave of the plague, which swept through Europe in the 14th century and killed 25 to 50 million people. Caused by the bacterium Yersinia pestis carried by fleas (often on rats), the human toll was roughly one-third of Europe's population at the time.

Hear how the Black Death reshaped Europe's economy

The Black Death killed tens of millions across Europe, but the labor shortages that followed shifted economic power. With fewer workers available, survivors demanded higher wages and better conditions—sparking what historians call a medieval “Golden Age of Labor.”

Europe’s first recorded influenza pandemic swept the continent in 1580

The 1580 influenza pandemic, traced from Asia to Africa and into Europe, became the first flu outbreak clearly documented across the continent—killing tens of thousands and highlighting influenza’s potential for rapid global spread.

Measles reached global transmission during the 15th- and 16th-century Columbian exchange

Devastating diseases like smallpox, influenza, measles, and other viruses were largely introduced into the Western Hemisphere beginning with the 1492 arrival of Christopher Columbus and the ensuing age of exploration.

Mount Vesuvius' ancient Roman eruption may have literally boiled blood

Mount Vesuvius erupted in 79 CE, sending ash and debris far and wide, burying several cities and the people inside them. This article details the various ways the blast killed those in Herculaneum. This seaside town was hit with the same ash and debris as Pompeii, and it was also hit by a wave of volcanic gases estimated to be more than 500° Fahrenheit, about 260° Celcius.

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.

View the 10 biggest volcanic eruptions in recorded history

The Mount Tambora eruption in 1815 was the deadliest and released so much sun-blocking ash and gas that 1816 became known as “the year without summer.” The resulting global food shortages are estimated to have killed over 71,000 people.

Supervolcanoes can eject enough material to fill one-fourth of the Grand Canyon

Although extremely rare, their released material can trigger winters by blocking the sun and cooling the Earth’s surface for years. The Toba supereruption 74,000 years ago disrupted food chains and reduced the human population to a few thousand.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa

More than 70% of all new infectious diseases originate in animals. Referred to as zoonotic diseases, these are diseases that originate in animals and occasionally spill over or jump from animals to humans. Bats, mosquitoes, and primates have all been linked to spillover events. As human populations push further into previously uninhabited wilderness, animal-human contact increases, and disease spillover is inevitable.

Underwater volcanoes significantly contributes to marine extinctions during the Triassic period

An analysis of ocean basins in the Tibetan Plateau helped identify three major periods of volcanism—250-248, 233-231, and 210-208 million years ago—which released significant amounts of greenhouse gases, altering ocean chemistry. The low-oxygen conditions may help explain half of Earth's Triassic extinctions.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

Variola: the second-deadliest virus on Earth

Because it was declared eradicated in 1980, many forget smallpox is one of history's deadliest diseases—in its final century, it's estimated to have claimed 500 million lives. This 11-minute video from production studio Kurzgesagt takes a look at...

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.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Treating black fever can result in a complication that spreads the deadly disease

Black fever, a deadly parasitic disease second only to malaria, threatens more than 1 billion people across more than 83 countries. Also known as kala-azar or visceral leishmaniasis, the disease is caused by parasites that spread through sandfly...

Invasive species can harm infrastructure and threaten human health

The wildfires in Hawaii in 2022 were made worse by flammable invasive grasses introduced from Africa as livestock pasture, and Zebra mussels native to the Caspian and Black Seas have spread across Europe and the US, where they can clog power plant pipes. Invasive mosquitoes can carry diseases, such as dengue and malaria.

Play 17th-century death roulette

Before modern science and medicine, death was much harder to escape. Using real mortality records from London's Dreadful Visitation–a collection of all the Bills of Mortality from 1665–this interactive game gives you an idea of what may have possibly killed you during the Great Plague. Grow your appreciation for life today as you stumble upon causes of death like “livergrown” and “drowned at St. Katharine’s by the Tower”.

Marburg virus, related to Ebola, is also extremely deadly, and has no available vaccine.

How royal panic led to Europe's deadliest witch hunts

This article delves into the witch "panics" and hunts that roiled across Scotland between 1590 and 1662. The witch hunts in Scotland were unusually deadly, with the country having five times the average European execution rate per capita. Their...

The word 'vampire' appeared in the English-speaking world in the 1730s

However, earlier mentions of creatures with similar characteristics existed throughout Medieval Europe. For example, people often spoke of revenants—restless dead creatures who tormented the living. Historians believe these stories grew in popularity in part because of influence from the Catholic Church, which was emphasizing the idea of purgatory. These older revenant stories eventually influenced modern vampire folklore.

Portugal's 1775 earthquake is considered Europe's first modern natural disaster

An 8.5-magnitude earthquake off the Portuguese coast nearly destroyed Lisbon, killing thousands, creating 16-foot-wide fissures in the city, and triggering a massive tsunami. Historians credit it with jump-starting the Enlightenment in the region, with many thinkers seeking natural explanations.

Pneumonia was once a leading killer before penicillin treatments

In the early 20th century, pneumonia was a top cause of death worldwide, often fatal without effective treatment. Penicillin turned a once deadly infection into one of the most treatable bacterial diseases.

Volcanic ash is composed of fragments of volcanic rock, minerals, and glass

These abrasive particles are hazardous to aircraft. They can melt within engines and re-solidify on turbine blades, preventing forward propulsion. If inhaled, chemicals within ash can be toxic, and the particles can embed themselves into the lungs' ducts, causing suffocation.

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

Viking raids spread Scandinavian culture far beyond northern Europe

Between roughly 800 and 1200 CE, seafaring Vikings from Scandinavia combined skilled craftsmanship with violent coastal raids. Their expeditions extended cultural influence from the British Isles to Northern Africa, reshaping medieval trade, warfare, and settlement patterns.

Alexander the Great, Rudyard Kipling, and more may have died from food poisoning

Though it is hard to prove decades or centuries after their deaths, some researchers suspect that food poisoning killed a variety of historical figures, including US President Zachary Taylor in 1850: Some researchers believe he may have consumed food contaminated with *Salmonella*.

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.

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.

This real-time tracking of the hantavirus cruise ship outbreak in May 2026 offers a unique glimpse into the global reach of the outbreak and whether the virus sickened passengers and their communities around the world.

Lyme disease-causing bacteria predate any suspected biological weapons testing

Borrelia bacteria existed long before any US biological weapons program—or human presence in North America. One study comparing genomes of the bacteria behind Lyme disease collected samples of the bacteria over three decades and calculated that the bacterium has been in North America longer than humans, at least 60,000 years. Other work found related bacteria preserved in amber from millions of years ago.

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

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

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.

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

Massive blooms of microscopic plankton called dinoflagellates produce the neon blue light seen in glowing tides.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.

Exploring the Larry Bird punch that almost changed March Madness