Rheumatoid arthritis occurs when the immune system attacks cells within joints

Explore how the most commonly used words in the English language have changed from the 1950s to 2023.

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.

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.

Located on Ross Island in Antarctica, Mount Erebus is the southernmost active volcano on Earth and features a lava lake—one of eight known worldwide as of 2026—that erupts regularly.

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

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.

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.'

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

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.

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

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 the many different civilizations around the Mediterranean shift power from the year 2500 BCE to 0 BCE in this animated map.

Humans may have as many as 100,000 to 150,000 individual hairs on our scalps, growing at a rate of roughly 1 centimeter per month.

Light takes approximately eight minutes to travel from the sun's surface to Earth, but it takes thousands of years to reach the star's surface from its core—a distance more than 200 times shorter.

As part of the up to 15 pounds of seafood they consume daily, sea otters eat urchins that feed on kelp forests—sources of shelter and food to over 800 species—thereby making the marine mammal a keystone species.

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

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

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.

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

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.

Watch Dr. Laurence Peter explain his 'Peter Principle,' which states that people are promoted to their level of incompetence and explains why bosses aren't always good at their jobs.

Find out how important you are to AI tools when they generate text responses with this tool, which estimates the weights of people's names.

Watch President John F. Kennedy's speech on going to the moon

Explore 3D models of some of the most dangerous viruses, allowing us to understand these and other pathogens in new ways.

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

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

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.

Explore an interactive forecast of the future of the universe, from the return of Halley's Comet to the last light in the cosmos.

Experience 14 billion years of important moments in world history with this scrollable interactive timeline.

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

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

Miracle berries make things that normally taste acidic or sour, such as lemons, taste sweet, like sugar-coated candy, by binding a special protein called miraculin to taste buds.

A dog's nose can be up to 100,000 times more sensitive than a human's, and each possesses a secondary organ for smelling, which helps learn about other dogs when they sniff each other's butts.

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

Washing dishware before putting it in a dishwasher may reduce the appliance's effectiveness because it dynamically adjusts wash time and temperature based on a sensor that detects dirtiness.

'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.

See where your state ranked in an analysis of the best public school systems in the US.

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

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

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