Researchers once thought Stonehenge functioned as a precise astronomical computer

New scientific tools, such as radiocarbon dating and DNA analysis, have transformed what we know about who built Stonehenge.

Techniques such as radiocarbon dating, DNA analysis, and isotopic testing have revised scholars' understanding of Stonehenge. This article presents evidence suggesting that societies were more cooperative and less violent than earlier theories had suggested.

Stonehenge has produced wild origin stories

Built before the wheel was invented, Stonehenge inspired increasingly fantastical explanations—from a 12th-century tale of Merlin and Nephilim giants to 1960s claims that aliens built it alongside the pyramids.

Stonehenge is one of the world's most studied prehistoric sites and was built around the same time as the Great Pyramid of Egypt.

What Stonehenge sounded like

Researchers built the first scale model of the world's best-known prehistoric stone circle, Stonehenge, to study its acoustic properties. Built approximately 5,000 years ago, the landmark in southern England has puzzled historians for centuries, but...

Stonehenge may have functioned as an echo chamber designed to keep ceremonies secret from outsiders.

Acoustics researcher Trevor Cox discovered that Stonehenge acts like a concert hall, reflecting and amplifying sound. This video shows Cox demonstrating the effect using a scale model inside a soundproof studio.

Stonehenge was part of a much larger prehistoric landscape

Long before Stonehenge was built, the Salisbury Plain was already dotted with ceremonial sites, burial mounds, and large-scale earthworks. These landscape maps reveal a densely inhabited region shaped by sophisticated prehistoric communities with ambitious public projects.

The connection between druids and Stonehenge is a historical misconception.

Take a virtual tour inside Stonehenge, the stone monument built roughly 5,000 years ago.

Prehistoric visitors approached Stonehenge along a processional route known as the Avenue, where the sunrise of the summer solstice aligns with the sarsen stones. This interactive 3D tour recreates that experience with explainer videos and detailed sidebars.

The Antikythera mechanism: The oldest-known analog computer

A device now considered the world's oldest computer was pulled from a shipwreck more than 120 years ago. Known as the "Antikythera Mechanism," it is now believed to have allowed precise tracking of astronomical positions, and its sophistication overturned understanding of Ancient Greek capabilities.

More than 2,000 years ago, a hand-powered model of the solar system called the Antikythera mechanism—the oldest example of an analog computer—could predict solar eclipses.

Stonehenge was part of a continent-wide "henge" boom

While Stonehenge is the most famous, it was one of roughly 1,300 henges built across prehistoric Europe. This piece from the British Museum situates Stonehenge within the broader ceremonial tradition.

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.

Four astronomical discoveries from ancient Greece

Modern astronomy relies on making discoveries without being present on the planets, stars, galaxies, and other objects studied. Imagine the difficulty the ancient Greeks had studying them without computers and telescopes. Yet somehow they calculated precise measurements of planetary distances, sizes, and more. Read this page to learn more about early triumphs in astronomical science.

BBC Radio 4 tackles the history of Stonehenge

On this podcast, host Greg Jenner humorously unpacks Stonehenge’s biggest myths and mysteries—from what a “henge” actually is, to how alien theories emerged, and why the monument was once sold for just £6,000.

Explore Stonehenge up close with photos and a 3D model

This Google Arts & Culture gallery brings Stonehenge into sharp focus through Life magazine archives, Getty Images, and a rotatable Google Earth model—plus a virtual tour that is close enough to spot lichen on the 30-foot sarsen stones.

An artist recreated Stonehenge as a bounce house in 2012

Though Stonehenge is sacred to many modern druids and pagans, artist Jeremy Deller reimagined it as a giant inflatable bouncy house—touring Paris, London’s 2012 Olympics, and even Stonehenge itself.

Is the sun aligned with Stonehenge right now?

Twice a year, during the longest day and night, the sun’s path aligns ever so gently with the ruins of Stonehenge. During the summer solstice, viewers can see the sun’s rise crest the central heel stone. The winter solstice sees the sun set across the site’s altar stone. Use this interactive to tour the historic site and check its current skyscape.

A Bronze Age timber circle, nicknamed "Seahenge," discovered on an English beach in 1998, may have been built to trick a bird into staying through winter.

Watch the sunset at Stonehenge during the 2025 Summer Solstice

Each year, tens of thousands gathered at Stonehenge to witness the sun’s alignment with the stones during the solstice. Watch a replay of a lifestream of the event from 2025.

What the stars once meant to ordinary people

The stars were a crucial aid for ordinary human beings in premodern societies, acting as regular timekeeping phenomena and celestial navigators. Today, light pollution and modern technology have rendered the stars a mere aesthetic delight for most of us, but their significance in history remains. Watch this brief video to learn how premodern humans used the stars for navigation, mathematics, and more.

Early timekeeping tools included sundials, water clocks, and astrolabes

Astrolabes also provided a person's latitude based on the height of the stars in the sky, thus aiding in navigation. Incense and candle clocks relied on the constant burning rate of fire to track the passage of time based on premarked locations with equal-interval spacing.

Ancient Greek astronomer Hipparchus created accurate maps of the night sky way ahead of his time, with coordinates sometimes within a single degree of modern values.

From the Greek for 'star taker,' the astrolabe allowed individuals to tell time and determine their latitude based on the position of the sun or other stars, as well as calculate the height of objects.

See images of modern Druids who visit Stonehenge to celebrate the solstice

At the summer solstice, crowds at Stonehenge range from white-robed modern Druids with staffs and antler crowns to revelers with ox-horn trumpets or hula hoops—scenes regularly documented by photographers.

The hour originated from an ancient Egyptian astronomical system

The movements of astronomical objects, measured in a day and a year, form the foundation of our sense of time. The Egyptians divided each day and night into 12 time eras, using arbitrarily selected stars as references rather than movements of specific celestial objects.

Scientists are still confused how Machu Picchu was built

Machu Picchu, the 15th-century Inca city high in the Andes, continues to fascinate experts with its mysteries. The methods used to transport and carve its massive stones—some weighing 15 tons—remain unclear. Theories range from hundreds of men dragging the stones to innovative techniques like using expanding wet wooden wedges for precision carving.

How the ancients calculated Earth's size correctly

Watch this seven-minute video to hear Carl Sagan explain how ancient Greek polymath Eratosthenes correctly calculated the size of the Earth in the third century BCE. At some point, Eratosthenes noticed a discrepancy in the length of shadows cast in different cities during the summer solstice. This observation grew into a simple experiment that enabled Eratosthenes, the head librarian at the Library of Alexandria, to calculate the Earth's size precisely.

The Ishango bone suggests mathematics was born about 20,000 years ago

Ancient civilizations developed mathematical systems for various purposes, including the Egyptians for the construction of the pyramids and the Ancient Greeks for logical reasoning in theorems. However, these systems were predated by the Ishango bone—found in the Democratic Republic of the Congo—whose notches suggest a base ten system, prime numbers, and simple mathematical operations.

Earth's circumference was estimated over 2,000 years ago using geometry and shadows

By measuring the angle of the shadow cast in Syene when no shadow was cast in Alexandria, Eratosthenes used the distance between the two cities and trigonometry to estimate the Earth's circumference to within a few percentage points of the actual value.

Early 20th-century debates about horses with 'paranormal mathematical abilities' helped shape modern approaches to psychological research.

One researcher posed a theory that aliens played a significant role in human evolution

Researcher Zecharia Sitchin proposed that Sumerian cuneiform tablets revealed that Sumerian gods were aliens who landed on Earth in Mesopotamia and influenced the creation of modern humans. While his ideas gained cultural interest, they are widely rejected by mainstream scholars.

The accidental birth of radio astronomy and the benefits of a moon-based telescope

Detecting radio waves from distant celestial objects is complicated by noise from solar wind, which the nighttime side of the moon is shielded from. If lunar temperature extremes can be overcome, the environment may serve as an optimal future home for radio astronomy, a field that began in 1928 when a 30-meter-long directional antenna, mostly out of brass and wood, picked up signals from the Sagittarius constellation.

Asteroids were discovered by 18th-century planet hunters

While looking for a planet between Mars and Jupiter to coincide with an apparent mathematical pattern in the distances of known planets from the sun, a group calling themselves the "Celestial Police" discovered multiple objects that fell into a new classification.

Scientists validated Albert Einstein's theory of gravity by measuring the apparent positions of stars via their starlight as it traveled near the sun on its way to Earth during a total solar eclipse.

The team responsible for the first interplanetary sundials included Bill Nye

While reviewing designs for instruments to be carried by future Mars rovers, Nye suggested adapting the function of a calibration tool, which would be used by the Spirit and Opportunity rovers to help calibrate the brightness and color of their panoramic cameras on the Martian surface.

In the third century BCE, the Greek astronomer Aristarchus of Samos estimated the distance to the moon using geometry after measuring the length of Earth's shadow during a lunar eclipse.

By identifying patterns in the periodic movements of the sun, moon, and Earth, ancient civilizations realized that identical eclipses repeat about once every 6,585 days, known as the saros cycle.

Railroads and long-distance communication led to the development of time zones, with Greenwich established as the prime meridian—the longitude of 0 degrees—due to British advancements in star mapping and navigation.

Designed in 1937 by Harvard graduate student Howard H. Aiken, the 'Harvard Calculator' was used by the US Navy to solve advanced physics problems.

View historical records of solar observations and discoveries, from telescopes in the early 1600s revealing sunspots to NASA's Parker Solar Probe photographing the sun from within its outer corona in 2025.

The New Year's ball was based on a navigational tool

Robert Wauchope, a member of the Royal Navy, developed the contraption in 1818 so crews could know the time while out at sea. The ball would descend at the same time every day, allowing ships to set their clocks accordingly.

Examine a 3D model of the Rosetta Stone

One of the most famous archaeological finds of all time, the 1799 discovery of the Rosetta Stone helped unlock the secrets of ancient Egypt. Inscribed on the granite slab was the same passage in three languages: hieroglyphics, Old Egyptian, and Greek, which enabled scholars to decode the ancient language. Take an up-close look with this 3D model made up of more than 200 composite photos.

Scientists used to speculate about life on the moon

In the 17th century, Galileo's observations suggested the moon could be inhabited, leading to fictional speculations about lunar life. In the 19th century, stories were published claiming the discovery of various creatures, including human bats. The Apollo missions in the 20th century explored the possibility of life there, but further exploration showed this idea to be less likely than before.

The first proposed experiment in the search for extraterrestrial intelligence (SETI) began with the mathematician and astronomer Carl Friedrich Gauss, who is credited with the idea of drawing a right triangle and three squares on Earth's surface to signal to aliens using the language of mathematics.

The 'Celestial Police' accidentally discovered asteroids while planet hunting

The group was formed in 1800 to find a planet some astronomers believed existed between Mars and Jupiter. Prior to their disbanding in 1815, the group instead discovered Vesta, Juno, and other objects they would call asteroids.

Artificial lighting and modern practices like working late are linked with sleep shifts

An analysis of five adults participating in a German reality program that tasked them with living in a Stone-Age-like settlement for 2.5 months, provided some insights into how modern conditions may have shifted our circadian rhythms. The participants slept about 90 minutes more under these conditions, and went to bed earlier and rose earlier, raising questions about how circadian rhythms, sleep, and sleep quality are affected by modern lifestyles.

Why some people say the moon is made of cheese

Mental Floss digs into the history behind the fable, which dates back as far as the 1500s, when it was mentioned in "The Proverbs of John Heywood." Even NASA has gotten in on the joke, tweeting a (supposedly) doctored photograph showing the moon's expiration date.

Before alarm clocks, people relied more heavily on their circadian rhythms, humans hired to wake them, and on tools such as candle clocks that dropped pins in metal trays at roughly set intervals.

According to the Greek historian Herodotus, the first person to successfully predict a solar eclipse was the Greek philosopher Thales of Miletus in 585 BCE, with the resulting celestial event ending a half-decade-long war.

Ancient Greek told to kick rocks after claiming moon wasn't a deity

About 2,500 years ago, ancient Greek philosopher Anaxagoras theorized that the moon probably wasn't a goddess. This article explains how this belief led to his exile. Anaxagoras also argued the sun was just a burning rock, writing that it was the sun that illuminated the moon. According to this resource, this theory enabled Anaxagoras to accurately explain eclipses and lunar cycles.