The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

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

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.

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

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.

Computer scientists first started trying to optimize dating using computers in the 1950s.

'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.

Watch what would happen if you literally had all the money in the world.

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.

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

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

On a cruise ship, the average person uses about 50 gallons of water a day, which is treated by bacteria and onboard filtration systems, then stored until the ship can legally discharge the wastewater.

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.

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

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

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

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

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.

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

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

Author David Foster Wallace's 'This Is Water' speech provides guidance for adulthood.

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.

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.

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

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

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

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

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

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

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

'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.

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.

Researchers generally group gut bacteria into six different categories, with varying amounts of these microbes residing in different parts of the digestive tract.

See a 3D reconstruction of Tenochtitlan, the Aztec capital

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

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

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.

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.