The flat earth idea is one of the oldest cosmologies in human history, dating back thousands of years to ancient Mesopotamia and Egypt. But the version circulating today has a surprisingly specific origin: a self-taught English inventor in the 1800s who stared down a canal with a telescope and declared he’d proven the world wasn’t round. From there, the idea traveled through Victorian lecture halls, a mid-century society, and eventually YouTube, where it found an audience bigger than it had enjoyed in centuries.
Ancient Civilizations Imagined a Flat Disk
Long before anyone had the tools to measure the planet, most cultures described the world as some version of a flat surface beneath a domed sky. Ancient Egyptian and Mesopotamian records portray the Earth as a disk floating in a cosmic ocean with the heavens arching overhead. An Iraqi tablet dated to around 1000 BCE shows Babylon sitting at the center of a flat disk. The Greek philosopher Anaximander, writing in the 500s BCE, imagined Earth as a flat disk perched on top of a cylinder.
These weren’t conspiracy theories. They were intuitive, reasonable explanations from people working with what they could see. The ground looks flat. The sky looks like a dome. Without ships, telescopes, or mathematics, a flat disk was a perfectly logical model.
The Greeks Figured Out It Was a Sphere
The flat model didn’t survive Greek astronomy for long. Pythagoras, in the sixth century BCE, reasoned that if the Moon appeared round based on the way its light-and-shadow line moved through its cycle, then the Earth was likely round too. Aristotle strengthened the case with two observations: the constellations you could see in the sky changed as you traveled north or south, and during lunar eclipses, Earth always cast a circular shadow on the Moon. A flat disk would sometimes cast an oval or a line. A sphere always casts a circle.
By around 240 BCE, the Greek scholar Eratosthenes went further and actually measured the planet. He knew the sun shone straight down into a well in Syene (modern Aswan) at noon on the summer solstice. At the same moment in Alexandria, roughly 787 kilometers to the north, sunlight hit the ground at an angle of about 7.2 degrees. Using simple geometry, he calculated the Earth’s circumference at approximately 39,350 kilometers. The actual figure is about 40,075 kilometers. He was off by less than 2 percent, over two thousand years before satellites existed.
Medieval People Did Not Think the Earth Was Flat
One of the most durable myths in popular history is that medieval Europeans believed the Earth was flat and that Columbus had to convince them otherwise. This story is largely fiction, and it has a specific author: Washington Irving.
In 1828, Irving published A History of the Life and Voyages of Christopher Columbus, in which Columbus heroically confronts ignorant medieval scholars who insist the world is flat. It made for a gripping narrative, but Irving, the same writer behind “Rip Van Winkle” and “The Legend of Sleepy Hollow,” was far more interested in a good story than accurate history. In reality, educated Europeans in the Middle Ages understood the Earth was a sphere. That knowledge had never been lost. The actual debate before Columbus’s voyage was about the size of the ocean, not the shape of the planet.
Irving’s version stuck, though, and generations of schoolchildren grew up believing that flat earth thinking dominated the medieval world. It didn’t.
The 1800s: Samuel Rowbotham and the Bedford Level
The modern flat earth movement traces directly to one man: Samuel Rowbotham, a Manchester-born lecturer who had studied the Bible intensely as a child and belonged to a devout movement that saw science and religion as fundamentally hostile to each other. Rowbotham despised the discoveries of Isaac Newton and set out to dismantle them.
His weapon of choice was a six-mile stretch of perfectly straight, flat water in the English Fenlands called the Old Bedford River. In the 1830s, Rowbotham sent a boat along the full length of the channel with a flag mounted on its mast and watched through a telescope. On a globe with Earth’s accepted curvature, the flag should have disappeared below the horizon well before reaching the far end. Rowbotham declared he could see it the entire way, six miles out to Welney Bridge, and concluded this proved the world was flat.
He repeated the experiment five times over the next 30 years, always at the same spot, always with the same method, always claiming the same result. What Rowbotham either didn’t understand or didn’t acknowledge was atmospheric refraction: light bends as it passes through air of different temperatures near a water surface, which can make distant objects appear visible when they should be hidden by curvature. It’s the same phenomenon that creates mirages on hot roads.
None of that slowed him down. Rowbotham was a gifted public speaker who toured the country giving lectures and published a book in 1865 called Earth Not a Globe. He called his system “Zetetic Astronomy,” from a Greek word meaning inquiry, and built a following that would outlast him.
The Flat Earth Society Takes Shape
After Rowbotham’s death, his ideas were carried forward by followers who formed the Universal Zetetic Society. That group eventually faded, but in 1956, an Englishman named Samuel Shenton revived the cause by founding the International Flat Earth Research Society, based in Dover. Shenton’s model drew from both Rowbotham’s zetetic framework and his own interpretation of the Book of Genesis: a flat disk centered on the North Pole, with the South Pole reimagined as an impenetrable wall of ice marking the edge of the world.
Shenton’s organization struggled to grow. By January 1969, the same year NASA put astronauts on the Moon, membership had dropped to just 100 people worldwide. Shenton eventually found a successor in Ellis Hillman, a London lecturer and local politician, but the society remained a fringe curiosity for decades. It was the kind of thing people mentioned as a punchline, not a movement.
YouTube Turned a Fringe Idea Into a Movement
The flat earth idea had largely faded from public consciousness by the early 2000s. What brought it back was the internet, and YouTube in particular. The first mentions of “flat earth” on YouTube appeared around 2011, mostly as references or jokes. But within three years, videos making serious arguments for a flat earth began gaining traction, and by 2016, flat eartherism had become a full-fledged online movement organizing international conferences.
The revival was driven by a collision of forces unique to social media: conspiracy culture, distrust of institutions, religious fundamentalism, clickbait incentive structures, and recommendation algorithms that funneled curious viewers deeper into flat earth content. Celebrities added fuel. In 2016, the rapper B.o.B publicly declared his belief in a flat earth, drawing mainstream media attention. By 2017, flat earth communities had established dedicated channels and used YouTube as their primary communication platform.
Researchers who studied the phenomenon found it wasn’t a single coherent ideology but a fusion of influences, pulling from climate change denial, distrust of NASA, young-earth creationism, and a generalized skepticism toward any authority. The algorithm did the rest, connecting these scattered threads into what looked like a unified worldview.
How Many People Actually Believe It
A nationwide U.S. survey conducted by the Carsey School of Public Policy at the University of New Hampshire found that about 10 percent of respondents agreed the Earth is flat. That number is higher than most people expect, though it comes with important context: 9 to 19 percent of respondents said they were “unsure” about various conspiracy claims, suggesting that some of that 10 percent may reflect general distrust of institutions more than a firm cosmological commitment.
The generational breakdown is striking. Among millennials, 18 percent agreed the Earth is flat, compared to much lower rates among older generations. The same age group also showed the highest agreement with other conspiracy claims, including Moon landing denial (24 percent) and microchip vaccination theories (9 percent). The pattern suggests that flat earth belief correlates less with ignorance of basic science and more with a broader stance of institutional skepticism that took root online.
The flat earth idea, in other words, started as an honest attempt to describe a world people couldn’t yet measure. It was resolved by Greek mathematics over two thousand years ago. It was falsely revived as a medieval belief by a 19th-century novelist, given pseudoscientific framing by a Victorian canal experiment, kept alive by a tiny society through the space age, and then supercharged by an algorithm that rewards engagement over accuracy.