Thousands of constitutional amendments have failed

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.

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.

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.'

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

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

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.

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

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

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

Listen to audio clips from Hoover, a harbor seal named after its insatiable appetite, who learned to say English phrases such as 'hello there' and 'come over here.'

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.'

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

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

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.'

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.

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

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

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

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.

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.

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

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

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.

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

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.

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

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.

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.

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

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

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

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.

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

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

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

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

'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.

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

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

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