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

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.

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

Explore a detailed map of Odysseus' fictional journey from 'The Odyssey.'

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Explore the history of American restaurants through an archive of menus dating back to the early 1800s.

Watch an animated visualization of how the Large Hadron Collider works, including how particles are accelerated through a series of machines and how collision data is collected and distributed worldwide.

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.

One of the most famous portraits ever taken is 'Afghan Girl' (1984) by Steve McCurry, yet the subject Sharbat Gula went much of her life without being identified or benefitting from the image's success.

One of the most famous portraits ever taken is "Afghan Girl" by Steve McCurry. Sharbat Gula, the subject of the photo, was not credited until 2002 for her role in the famous National Geographic cover, and continued to live in poverty after the photo was taken.

'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.

The US has discontinued a variety of different currency denominations over the years—including a $100K bill.

On planets in systems with two stars, such as the fictional Tatooine from 'Star Wars,' observers would see overlapping rainbows and double rainbows.

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

See a breakdown of how some of the most common food items are traded across the globe, including the key trade relationships for each item.

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.

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

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

The world's largest waterfall is in the ocean and is more than three times the height of Angel Falls, the largest waterfall on land.

Peek into the love lives of thousands of strangers whom Stanford University researchers have been tracking since 2017 on this interactive page.

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

The Berlin Wall physically separated East and West Berlin for nearly three decades, preventing East Germans from fleeing to the West and earning the nickname 'the Iron Curtain.'

The US jobs projected to shrink the fastest over the next decade include typists and word processors.

There are up to 100 trillion microbes in the gut, and maintaining the relative balance in this ecosystem is important for our health.

Relax to a livestream of brown bears chilling in Katmai National Park in Alaska.

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

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

See a 3D reconstruction of Tenochtitlan, the Aztec capital

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.

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

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

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.

Explore an interactive timeline of Earth's 4.5-billion-year history to visualize shifting landmasses and oceans, view the locations of significant asteroid impacts, and learn about major geological and biological events.

Apeirophobia is the fear of everlasting life and may stem from the human brain's inability to conceptualize the concept of anything happening beyond what it can project out, such as the concept of an infinite life.

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.

Although the moon passes between the sun and Earth each month, its orbit is tilted by five degrees, preventing Earth from experiencing a solar eclipse each month.

Explore how temperatures compare to historical averages in cities worldwide with this interactive global monitor.

Experience a century of America's healthcare advances with this medical visualization, tracing a sampling of healthcare innovations from head to toe.

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

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks.