Sea stars are invertebrates—they lack a backbone—and while most exhibit pentametric radial symmetry due to having five arms radiating from a central disk, some can possess more than 40.

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

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.

Metamorphosis evolved over millions of years as species that hatched as smaller versions of adults started exhibiting genetic mutations that differentiated juvenile and adult bodies.

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

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

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.

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

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.

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.

This interactive website features nearly 40,000 photos from Wikipedia for you to create visual mosaics with.

Examine this captivating animation 'building' a human—illustrating the roughly 40 weeks of fetal development.

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

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

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

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.

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

The tallest tsunami in recorded history was 524 meters (1,720 feet) high—taller than the Empire State Building—and occurred in Lituya Bay, Alaska, in 1958 after an earthquake dislodged a rockface into the water.

Humans tend to imagine aliens as humanlike, but that's probably unlikely. Three different hypothetical planets show how aliens' bodies could take many forms.

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

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.

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

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

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.

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

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

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

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.'

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.

Fecal transplants can help treat infections by transplanting healthy gut bacteria from a donor into a patient's gastrointestinal tract using samples of human waste, which are turned into a liquid mixture and often delivered via a colonoscopy procedure.

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.'

If the moon were less than one-twelfth its current distance from Earth, the planet's tidal forces would overcome the moon's internal gravity, tearing it apart and forming a ring of debris.

'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.

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.

George Lucas used Joseph Campbell's 'hero's journey,' a narrative structure that encompasses the common characteristics of multiple cultures' mythologies, to revise 'Star Wars.'

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

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

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

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.