The collapse of gas bubbles in the joint synovial fluid causes 'cracking' knuckles.

Male pattern baldness accounts for more than 95% of hair loss in men and is characterized by thinning hair, hair loss, and a receding hairline.

Watch footage from the moments the Titanic wreck was discovered by a joint US-French research team in 1985.

There are 'YouTube camps' that teach children how to create content for the video platform.

Joan Didion interviewed The Grateful Dead in 1967, before they became music icons.

The animatronic shark from 'Jaws' was a complex machine called 'Bruce.'

Give your memories a place to live and explore the personal stories left by strangers, tied to specific locations, in this interactive map of the world.

Pregnancy makes someone more attractive to the mosquito species that transmits malaria.

Watch 4-plus decades of Pixar's opening logos.

In 1962, the US detonated a nuclear weapon in space, which produced an electromagnetic pulse that disabled three low Earth orbit satellites and damaged electrical equipment in Hawaii.

Cats have a mutation that prevents them from tasting sweetness, and goldfish rank among the world's supertasters.

Play the role of a student as you try to navigate college and remain debt-free.

Between 2002 and 2012, at least 12 people were killed in the Philippines in incidents related to off-key karaoke singing of Frank Sinatra's 'My Way.'

The final shots of the Civil War were fired in the Arctic over 2 months after the South's surrender.

Simulations suggest that a paper airplane launched from the International Space Station would maintain its orientation and gradually descend for 3.5 days before chaotically tumbling down and burning up.

Robert Smalls escaped slavery by piloting a stolen Confederate ship to freedom, then became an influential Black political leader during Reconstruction.

'Bibliotherapy' is of increasing interest as a way to improve mental health and help navigate complex life situations—with people immersing themselves in the experiences of fictional characters or nonfiction and self-help books to find relief and gain personal insights.

Here are some tips from Pew Research to help you distinguish between a good poll and an unreliable one.

Stonehenge was built using giant wooden rollers and precisely carved tongue-and-groove joints to lock the stones in place.

This short animation shows how human beings managed to lug 30-ton stones over miles of prehistoric English countryside and stand them up The Stone Age engineering involved using giant wooden rollers and carving precisely interlocking tongue-and-groove joints to hold the heavy stones in place.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

Plato's famous allegory of the cave is a metaphor exploring the value of truth over ignorance.

Explore the 2025 Uber Lost & Found Index to find out the weirdest items that passengers left behind in Ubers last year, from ten live lobsters to a mannequin head with human hair.

Abraham Lincoln had to sneak into Washington, DC, in disguise for his 1861 inauguration after a detective uncovered a plot to assassinate him in Baltimore.

If a source of music traveled past someone at twice the speed of sound, assuming sufficiently sensitive hearing and powerful equipment, they would hear the music backward.

Watch a visualization of what it would look like to move along Earth's surface as fast as the International Space Station, or about 23 times the speed of sound.

Lake Sørvágsvatn sits about 32 meters (105 feet) above sea level, but the taller surrounding cliffs create an optical illusion that makes it appear to float much higher above the ocean.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

Explore Lewis and Clark's 8,000-mile journey in Google Earth.

Emanuel Leutze's painting 'Washington Crossing the Delaware' is one of the defining images of the Revolutionary War.

You may be better at spotting a lie when listening to a speaker's voice inflections rather than watching for facial and body cues.

The Aztec Empire ruled over 80,000 square miles of central Mexico for nearly a century—until a small band of Spanish conquistadors brought it down in 1521.

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

'Tulip mania,' the 1630s Dutch craze where rare bulbs were briefly traded like luxury assets, may have been the first financial bubble—and it still shapes markets today.

Watch a breakdown of the canine family tree that explains how foxes and wolves are related to our beloved household pets, like poodles and dachshunds.

Watch Bruce Springsteen's 1985 performance of Woody Guthrie's 'This Land Is Your Land,' which he calls 'the greatest song ever written about America.'

Check out some of the best books that can be read in a single day, with titles from Han Kang, Denis Johnson, Muriel Spark, and more.

Explore a collection of famous literary maps, including original images from 'Treasure Island,' 'The Swiss Family Robinson, ' and 'Walden.'

The average banana produces one positron—the antimatter counterpart to an electron—every 75 minutes as its trace amounts of radioactive potassium decay.

'Golden blood' is the rarest blood type in the world—fewer than 50 people are known to have it.

Rapid intensification is the increase in a hurricane's sustained wind speed by at least 35 miles per hour within 24 hours, which can strengthen it by up to two categories.