An ‘ultramarathon’ is any race longer than a marathon

Ultrarunning has grown exponentially in the 21st century

Ultrarunning, generally defined as races 50k and longer, has exploded in the past few decades. In 2000, there were 89 official races; in 2023, there were nearly 760. That's a 753% increase.

The marathon is only getting more popular

The marathon has become a part of popular culture, with races in nearly every major city. The largest is the New York City Marathon, which started in 1970. Over 55,000 runners participated in the 2024 race. Its popularity doesn’t appear to be slowing, with younger generations increasingly lacing up their shoes for the race of a lifetime.

Why marathons are 26.2 miles (not 26)

Over 1,100 marathons are run every year, and they all share one oddly specific distance: 26.2 miles. From ancient Greece to a British queen's request, here's the surprising story behind the marathon's decimal.

The most challenging marathons in the world

Even on a flat course, the event is a taxing ordeal. Now imagine those 26.2 miles climbing some of the world’s highest mountains (via the Tenzing Hillary Everest Marathon or the Kilimanjaro Trail Marathon), across the Great Wall of China, or trekking up the Inca Trail. These races won’t earn you a PR, but they will make for good stories.

The marathon was not an event in the ancient form of the Olympics

The ancient Olympics started with just one footrace, a roughly 3-mile jaunt dubbed the "dolichos." Over the centuries, it blossomed into multiple running events, field events, combat sports, and equestrian events—all performed in the nude. This list showcases eight more lesser-known facts about the ancient Games.

The oldest marathoner was 100

Fauja Singh was 100 when he completed the Toronto Waterfront Marathon in 2011 at 8:11:06. Incredibly Singh didn't start running until the age of 89.

The beer mile blends running and drinking

The event requires competitors to drink a 12-ounce beer for every lap around the track. It may sound like fun (or a nightmare, depending on your disposition), but for some it's a serious business, with an annual world championship.

Endurance art strains and exhausts the body

Artists like Marina Abramović are known for testing the limits of human endurance. Endurance art can involve carrying heavy objects or posing uncomfortably for long durations. (This resource contains some artistic depictions of violence.)

Eliud Kipchoge broke the 2-hour mark in a 2019 exhibition

In 2019, Kenya's Kipchoge ran 1:59:40.2, though it was part of an exhibition that included numerous aids—including elite runners cutting his wind and a laser marking the necessary pace—not permitted in officially sanctioned events. As such, it is not eligible for the world record.

An impostor convinced Frank Shorter he’d lost the gold

The 1972 marathon at the Munich Games featured a dramatic finish, thanks to someone posing as a competitor entering the stadium before Shorter. The stunt confused Shorter and the crowd (and enraged the American television announcers) as he entered the final stretch.

On one sailor's race to sail around the world solo

People wanting to sail around the world in modern times can sign up for the Golden Globe Race, a decades-old, organized sprint to circumnavigate the world by ship. This long-form article follows one woman's journey as she attempted to complete the...

The ultraviolet catastrophe is the infinite energy prediction of classical physics

When scientists first tried calculating the radiation emitted by a heated object, their assumption was that energy was equally distributed across wavelengths and produced infinite energy at low wavelengths. This contradicted observations, which showed near-zero energy intensity at those values.

The X Games is an annual extreme sports competition

The official X Games site offers event schedules, athlete profiles, competition results, and news for both summer and winter editions—along with videos and highlights from skateboarding, BMX, motocross, and other action sports.

The longest word in English is 189,819 letters long

The wildly-winding word (so long that we can't fit it here) is the proper name for titin, a protein that keeps muscles elastic.

Ultraprocessed foods include preservatives, dyes, sweeteners, and more

Processed foods are those that have been altered from their original state, which includes numerous processes that we consider natural, such as cooking or salting. Ultraprocessed foods contain at least one item that wouldn’t be found in a kitchen, like hydrogenated oils or high-fructose corn syrup. It’s estimated that nearly 75% of all foods consumed in the US are ultraprocessed, though that doesn’t mean that all of them are unhealthy. In fact, some, such as prepackaged whole wheat bread and soy milk, are recognized for their health benefits.

What is the unlimited marital deduction?

One big way to avoid paying several death taxes? Get married. The unlimited marital deduction allows an individual to grant all their financial assets to their spouse while they're alive or after they’ve died without having to pay the federal estate tax or gift tax. There are limitations to this rule. For instance, how it works with state death taxes. Learn more here.

The Triple Crown, explained

Only 13 horses have ever won the Triple Crown—one of the most elusive titles in American sports. This explainer breaks down how the series works, why it's so difficult to win, and the legendary horses that defied the odds across the Kentucky Derby, Preakness Stakes, and Belmont Stakes.

Health span: The number of years one is active and disease-free

As scientific advances continue to extend the average human lifespan, many are now turning their attention toward extending "health span." The ultimate goal would be to extend one's health span to match one's lifespan, which would necessitate a shift in focus toward the pursuit of healthy aging. (Some users may experience a paywall.)

Cancer is runaway growth of abnormal, mutated cells

Cancer cells have mutations in their DNA that allow uncontrolled growth and division, dodge usual mechanisms of cell death, and can often spread throughout the body. This is, in part, why the disease is so difficult to treat, with a wide variety of mechanisms and types that poses unique challenges.

Formula 1 cars are the world's fastest regulated road-course racing automobiles

F1 is the highest international level of open-wheel racing, where the wheels are not covered by the car’s body, differing significantly from NASCAR, which have covered wheels.

Racketeering is broad term for running an illegal scheme

Racketeering itself isn't a single crime and prosecutors tend to think about racketeering as a pattern of criminal activities, including kidnapping and money laundering. The term comes from the Racketeer Influenced and Corrupt Organizations Act, known as RICO.

The gray area that makes PEDs seem like leveling up to hardcore athletes

Doping in sports is broadly condemned as unsafe and unfair. Significant controversies in major sports, including baseball and cycling, have been prompted by the widespread use of performance-enhancing drugs, which are described as clear-cut dangers and abuses of the rules. But to many competitors, the line between a PED and the next smart technique to adopt is unclear. This podcast episode explores that gray reality.

Frisbee, Jet Ski, and Dumpster—explore a list of words you might not realize are trademarked

Many products that have become household names started out as first-of-a-kind items. As those products grew in popularity, the brand name became the default name for the product.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

What is a heat dome?

The world is seeing regular heat waves with multiple causes, including so-called "heat domes," a term rising in use in recent years. A heat dome occurs when the atmosphere traps hot ocean air like a lid or cap, creating stifling conditions and resulting in extended periods of heat. See an illustration of this phenomenon and read how it works with this brief explainer.

Read a technical review of extremophile categories, including the habitats of each

Acidophiles can survive in environments with acidity greater than that of the human stomach, and some radiophiles can live in places with radiation exposure hundreds of times higher than what is lethal to humans. Piezophiles—formerly known as barophiles—have been found in the Mariana Trench, where pressures are over 1,000 times larger than those on Earth's surface.

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.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

The 1987 Nintendo video game 'Stadium Events' isn't known for being particularly fun, but its scarcity has made it a highly sought-after item that has sold for up to $35K at auction.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

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

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

See the 25 of the best photos of auroras from around the world.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Fireworks make a loud booming sound after exploding due to air expanding faster than the speed of sound.

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

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

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

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Urushiol, the oily toxin in poison ivy, can remain allergenic on clothing for years.

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

Explore a list of the 100 best novels of all time, compiled by some of the world's best living writers, including Salman Rushdie, Stephen King, and Jennifer Egan.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.