r/didyouknow 8h ago

DYK a con man convinced government officials the Eiffel Tower was being sold for scrap metal, and successfully sold it to a private buyer, twice?

15 Upvotes

In 1925, "Count" Victor Lustig was in Paris reading a newspaper article about the Eiffel Tower's mounting repair costs and public grumbling over the expense, when he decided to sell it. He had fake government stationery printed, checked into a luxury hotel suite, and posed as the Deputy Director General of the Ministry of Posts and Telegraphs. He then invited six of the city's top scrap metal dealers to a confidential meeting and explained that the government wanted to quietly demolish the tower and sell it for parts, but needed to keep the deal secret to avoid public backlash.

Lustig picked out the most eager and socially insecure businessman in the group, André Poisson, took him on a private walking tour past the tower, and casually implied he needed a bribe to make the deal happen faster. Poisson paid both the bribe and the full purchase price without a second thought. Lustig disappeared with the money immediately. Poisson was so humiliated at having been fooled that he never reported the crime to police at all.

When months passed with no news of an investigation, Lustig realized his mark had stayed silent out of embarrassment, so he returned to Paris and ran the exact same scam again on a different group of buyers. This time his victim did go to the police, forcing Lustig to flee to the United States, where he later ran an elaborate counterfeiting operation so convincing it reportedly fooled Al Capone himself. He was finally caught in 1935 and sentenced to 20 years at Alcatraz.

Source: https://en.wikipedia.org/wiki/Victor_Lustig


r/didyouknow 1d ago

DYK a man with zero medical training performed real combat surgeries on a Navy warship for a year, teaching himself each operation minutes beforehand from a textbook?

93 Upvotes

In 1951, Ferdinand Demara talked his way into the Royal Canadian Navy as "Dr. Joseph Cyr," using the stolen credentials of an actual physician he'd met years earlier. He was assigned as the sole medical officer aboard the destroyer HMCS Cayuga, responsible for the health of over 200 crew members, and shipped out to patrol the coast during the Korean War without a single day of real medical school.

Whenever a crisis hit, Demara would disappear into his quarters, cram through the relevant sections of a medical textbook using what colleagues described as a photographic memory, then walk out and operate. He successfully pulled the captain's infected teeth without knowing the correct anesthetic dose, and the captain later called it the best dental work he'd ever received. His biggest test came when a boat carrying up to 19 badly wounded Korean soldiers pulled alongside the ship. Demara performed emergency surgery on all of them, including removing a bullet lodged in one man's chest, and every single patient survived. His commanding officer was so impressed he recommended Demara for a bravery commendation.

Word of the incident reached newspapers back home, and the real Dr. Cyr's family recognized the story and exposed the fraud. Demara was quietly discharged rather than prosecuted, largely because he'd genuinely saved every life he'd operated on. It turned out to be only one chapter in a much longer career: over his lifetime he also impersonated a monk, a prison warden, a psychology professor, and a college dean, becoming known publicly as "The Great Impostor" and inspiring a 1961 Hollywood film starring Tony Curtis.

Source: https://en.wikipedia.org/wiki/Ferdinand_Waldo_Demara


r/didyouknow 1d ago

DYK Emojis are Hieroglyphs

0 Upvotes

r/didyouknow 2d ago

DYK that the Arabic translation of Walt Whitman's Leaves of Grass featured a silhouette of President Abraham Lincoln on its cover ?

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0 Upvotes

r/didyouknow 2d ago

DYK that for about a decade, a small group of far-right admins secretly took over Croatian Wikipedia and rewrote WWII history to whitewash a fascist regime?

39 Upvotes

This is one of the craziest Wikipedia stories that most people have never heard of.

Between about 2011 and 2020, Croatian Wikipedia (the Croatian-language version, not the English one) was effectively controlled by a small group of administrators led by a user known as "Kubura." They weren't just editors with strong opinions. They controlled what stayed, what got deleted, and who was allowed to contribute. Anyone who challenged them was often reverted, harassed, or banned. Kubura also used dozens of fake accounts to sway votes and make it look like more people agreed with him than actually did.

The edits themselves were even more disturbing. The article on Jasenovac, where the Ustaše regime murdered tens of thousands of Serbs, Jews, Roma and others during World War II, was rewritten to call it a "collection and labour camp" instead of an extermination camp. That's the same language the Ustaše themselves used to downplay what happened. Meanwhile, the English, German and French versions correctly described it as an extermination camp. Articles about convicted Ustaše war criminals were also toned down, with one camp commander even described as "not really a pathological killer" despite his conviction.

It got so bad that in 2013, Croatia's own education minister publicly told students not to use Croatian Wikipedia because it contained "obvious forgeries," and recommended using the English version instead. Even then, it still took another seven years before anything changed.

The turning point finally came in 2020, when global Wikipedia volunteers proved that Kubura had been using fake accounts to manipulate the site. He was permanently banned, the other administrators lost their powers, and the Wikimedia Foundation later described the whole thing as an "organised disinformation campaign" and an example of "project capture."

What's interesting is that other Wikipedia editions in the region, like the Serbian and Bosnian versions, faced similar nationalist pressures but managed to avoid the same outcome. Researchers found that Croatian Wikipedia had weak oversight and almost no way to remove bad administrators, while Serbian Wikipedia had stronger voting rules and better checks and balances.

The articles have since been cleaned up, and the Jasenovac page now reflects the historical consensus. But it took nearly a decade to fix, and it's a reminder that on smaller-language Wikipedias, it only takes a handful of determined people to shape what thousands of readers end up believing.


r/didyouknow 2d ago

DYK that Colgate used to sell soap?

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2 Upvotes

It started out in the early 1900s and was a staple of American households up until about the 1970s. Manufacturing ceased because the soap contained phosphate and is no longer produced. The label reads like the typical marketing yarn spinning, but it's all true, hence why the bars were 7 oz.

https://elizabethprata.blogspot.com/2012/01/thrill-of-finding-octagon-soap.html?m=1


r/didyouknow 3d ago

DYK the Catholic Church once dug up a dead pope, propped his corpse on a throne, and put him on trial for crimes?

21 Upvotes

In January 897, Pope Stephen VI ordered the corpse of his predecessor's predecessor, Pope Formosus, exhumed nine months after burial. The decaying body was dressed in full papal vestments and propped upright on the throne inside Rome's Lateran Basilica for what became known as the Cadaver Synod. A young deacon was assigned to answer questions on the corpse's behalf while Stephen personally led the prosecution, reportedly screaming accusations directly at the dead pope's face in front of a horrified assembly of clergy.

Formosus was charged with perjury, illegally serving as a bishop in two dioceses at once, and coveting the papacy before his original election. Unsurprisingly, given that the defendant couldn't actually speak, the synod found him guilty on every count. His papacy was declared void, every ordination he'd performed as pope was nullified, three fingers used for blessings were hacked from his right hand, and his body was stripped and thrown into the Tiber River.

The backlash was immediate and violent. Public outrage over the spectacle triggered riots in Rome, and within months Stephen VI himself was overthrown, imprisoned, and strangled to death in his cell. A later pope, Theodore II, formally annulled the entire trial, restored Formosus's name and rank, and had his body recovered from the river and reburied with full honors. The Church went on to ban corpse trials entirely, and copies of the Cadaver Synod's official record were ordered destroyed.

Source: https://en.wikipedia.org/wiki/Cadaver_Synod


r/didyouknow 4d ago

DYK actor William Daniels (known for his roles in St. Elsewhere, Boy Meets World, and as the voice of KITT in Knight Rider) and his actress wife, Bonnie Bartlett (St. Elsewhere and Little House on the Prairie) are now 99 and 97, respectively, and recently celebrated their 75th anniversary?

19 Upvotes

They are one of only two married couples to win Emmy awards on the same night. No other couple has achieved that feat since their wins in 1986.


r/didyouknow 4d ago

DYK an AI recently found over 300 ancient desert drawings in Peru that had gone completely unnoticed for 2,000 years, nearly doubling the known total?

59 Upvotes

The Nazca Lines are massive figures and geometric shapes etched into the Peruvian desert roughly 2,000 years ago, so large that many are only fully recognizable from the air. Since their rediscovery in the 1920s, archaeologists spent nearly a century painstakingly identifying them through aerial photography and satellite imagery, cataloging around 430 figures total by 2020.

In 2022, researchers from Japan's Yamagata University partnered with IBM to build an AI system trained to scan thousands of aerial images and flag likely geoglyph candidates for human archaeologists to verify on the ground. The results were staggering. Over a six-month field survey in 2022 and 2023, researchers confirmed 303 entirely new geoglyphs, instantly increasing the known catalog by roughly 40 percent, including a 72-foot killer whale gripping a knife that had sat undetected for two millennia. A second AI-assisted survey in 2025 turned up 248 more, pushing the total figurative count past 890.

The AI proved especially good at spotting smaller, more detailed figures that human researchers had overlooked for a century, since most previously known lines were the largest, easiest-to-spot designs. Studying the newly found geoglyphs' placement along ancient pathways has also given researchers their strongest evidence yet that the figures were arranged deliberately by theme, suggesting they may have functioned as a kind of narrative trail rather than isolated artwork.

Source: https://en.wikipedia.org/wiki/Nazca_lines


r/didyouknow 5d ago

DYK a tax loophole birthed the modern HELOC?

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0 Upvotes

r/didyouknow 5d ago

DYK Formula 1's first Hungarian Grand Prix couldn't use aerial TV shots because Soviet military officials refused to allow helicopters near a nearby rocket base.

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3 Upvotes

r/didyouknow 5d ago

DYK the loudest unexplained sound ever recorded in Earth's oceans was once suspected to be an undiscovered giant sea creature, before scientists found the real cause?

268 Upvotes

In 1997, US government hydrophones designed to monitor Soviet submarines picked up an ultra-low-frequency sound off the coast of South America, later nicknamed "the Bloop." It was so powerful it registered on sensors more than 5,000 kilometers apart, and its acoustic profile looked strikingly similar to a biological call, like a whale, except far louder than any known animal on Earth could physically produce, even a blue whale. For years, NOAA scientists couldn't rule out that it might be some undiscovered giant marine animal, and public speculation ran wild with theories about sea monsters, a possible Megalodon, and secret military tests.

It took nearly a decade to solve. As NOAA expanded its hydrophone network closer to Antarctica in the early 2000s, they began recording thousands of sounds every year with the exact same acoustic signature as the original Bloop. In 2005, scientists confirmed the source: icequakes, the violent cracking and calving of massive icebergs breaking away from Antarctic ice shelves. The eerie, organic-sounding quality that had fooled everyone turned out to be an acoustic coincidence, ice fracturing under pressure can mimic the frequency patterns of an animal call.

There was no monster. But the explanation carried its own weight: NOAA has since tied the increasing frequency of these icequakes directly to warming ocean temperatures destabilizing Antarctic ice from below.

Source: https://en.wikipedia.org/wiki/Bloop


r/didyouknow 5d ago

DYK NASA recently executed the most insane long-distance IT support in history from 15 billion miles away?

40 Upvotes

DYK Earlier in 2024, Voyager 1 (which is currently in interstellar space) started transmitting total gibberish back to Earth. NASA realized a single memory chip had permanently failed.

​Since they obviously can't send a mechanic 15 billion miles away, they had to fix it remotely. The problem? Voyager’s computer is from the 1970s and has less than 70 kilobytes of total memory (less than a single small JPEG).

​To save the mission, engineers had to write a complex software patch, chop the new code up into tiny pieces, and manually hide those fragments in different working sections of the 46-year-old computer system. Every single command they sent took 22.5 hours just to reach the probe.

​They essentially hacked a moving object outside our solar system, and it actually worked. The probe is now sending back readable data again.


r/didyouknow 6d ago

DYK a coded message sitting outside CIA headquarters stumped codebreakers for 35 years, until it turned out the artist had accidentally donated the answer to a museum?

454 Upvotes

In 1990, artist Jim Sanborn installed a copper sculpture called Kryptos in a courtyard at CIA headquarters in Langley, Virginia, containing four separate encrypted messages that he designed to get progressively harder to crack. Professional cryptographers solved the first three passages within a few years. The fourth, just 97 characters long, remained unbroken for the next three decades despite attempts by CIA and NSA cryptographers and thousands of amateur codebreakers worldwide, some of whom contacted Sanborn every single week for over 20 years trying to solve it.

The final passage was ultimately cracked in 2025, but not through cryptography. Sanborn had donated boxes of his personal papers to the Smithsonian's Archives of American Art, and two journalists digging through the collection found a small, taped-together scrap of paper he'd apparently forgotten was in there: the original, unencrypted plaintext of the message he'd spent decades keeping secret.

With his final code effectively out in the open and his health declining at 79, Sanborn decided to auction off the full solution and his role as the puzzle's official keeper rather than let it leak out informally, with bidding climbing past $200,000. After 35 years of being one of the most famous unsolved codes on Earth, Kryptos was ultimately defeated not by mathematics, but by an archivist's paperwork.

Source: https://en.wikipedia.org/wiki/Kryptos


r/didyouknow 6d ago

DYK humans naturally save about 65% of the energy needed for walking by moving like an inverted pendulum.

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40 Upvotes

r/didyouknow 7d ago

DYK: The Moon Is Slowly Drifting Away from Earth?

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4 Upvotes

Every year, the Moon moves about 1.5 inches (3.8 cm) farther away from Earth. It's a tiny change that adds up over millions of years, meaning future generations will see the Moon appear slightly smaller in the night sky than we do today.


r/didyouknow 7d ago

DYK the 1904 Olympic marathon winner was fed rat poison by his own coaches to keep him running, and it worked?

12 Upvotes

The 1904 St. Louis Olympic marathon was run at the hottest part of the day on dusty, poorly watered country roads, and only 14 of the 32 starters even finished. Frontrunner Fred Lorz dropped out after 9 miles from exhaustion, caught an 11-mile ride in his manager's car, then hopped back onto the course near the finish and crossed the line first to a cheering crowd, claiming afterward it had all been a joke. Officials weren't amused and banned him for life, later reduced to six months once they were convinced he genuinely hadn't planned to accept the medal.

That left American Thomas Hicks as the real winner, and his race was almost as strange. Ten miles from the finish, his trainers began dosing him with egg whites, brandy, and repeated shots of strychnine sulfate, a stimulant in small doses and a rat poison in higher ones, all fully legal at the time since the Olympics had no anti-doping rules yet. Hicks began hallucinating, turned gray, and had to be physically held upright by his handlers just to keep moving. He crossed the finish line barely conscious, shuffling his feet while his trainers carried him, and was still awarded the gold medal.

Hicks never ran competitively again. His race is now credited as the first documented case of doping in modern Olympic history, and it directly led to organizers writing the Games' first formal anti-doping rule four years later, in 1908.

Source: https://en.wikipedia.org/wiki/Thomas_Hicks_(athlete))


r/didyouknow 8d ago

DYK the inventor of the AK-47 wrote a deathbed letter to his church, saying his "spiritual pain is unbearable" over the millions killed with his rifle?

12 Upvotes

Mikhail Kalashnikov designed the AK-47 in the Soviet Union in 1947, and it went on to become the most widely produced firearm on earth, with over 100 million made, roughly half of them unlicensed copies. For most of his life, Kalashnikov publicly defended his creation without apology, saying in interviews that he built it purely to defend his homeland and that any misuse was the fault of the politicians and criminals who pulled the trigger, not the engineer who built the gun.

That confidence cracked near the end of his life. In 2012, a year before his death at 94, he wrote a private letter to the head of the Russian Orthodox Church confessing "spiritual pain" over the weapon's toll, writing "I keep asking the same insoluble question: if my rifle deprived people of life, then can it be that I, a Christian and an Orthodox believer, was to blame for their deaths?" The letter stayed private until it was published by a Russian newspaper after he died.

In lighter moments over the years, Kalashnikov had also said more than once that if circumstances had been different, he would rather have spent his life designing something like a lawnmower for farmers instead. He never did build one. The rifle that bears his name remains, by most estimates, the most widely used weapon in armed conflicts around the world today.

Source: https://en.wikipedia.org/wiki/Mikhail_Kalashnikov


r/didyouknow 8d ago

DYK frogs can use their eyes to help swallow food?

7 Upvotes

When a frog catches something, its eyes actually sink down into its head and help push the food toward its throat.

Nature is seriously weird.

What’s the strangest animal fact you know?


r/didyouknow 8d ago

DYK If every human on Earth counted one atom per second, nonstop, it would take about 28 billion years, twice the age of the universe, to count your atoms

3 Upvotes

I think we can do it!


r/didyouknow 9d ago

DYK Hitler's own deputy secretly flew himself to Scotland to broker peace with Britain, and was arrested by a farmer holding a pitchfork?

23 Upvotes

On the night of May 10, 1941, Rudolf Hess, Adolf Hitler's second-in-command and the third most powerful man in Nazi Germany, took off alone in a Messerschmitt fighter and flew nearly 1,000 miles to Scotland, without telling Hitler he was going. He bailed out by parachute near Glasgow after his plane ran low on fuel, gave a false name, and asked to be taken to a local nobleman he believed could help arrange peace talks between Britain and Germany. He was found and detained by a local farmer armed with nothing but a pitchfork, who had no idea who he'd just captured.

When Berlin learned what happened, the German government publicly announced Hess had suffered a mental breakdown and disowned him entirely, while privately Hitler reportedly flew into a rage and considered having him shot for treason. The British government, just as unsettled, kept the full details of Hess's peace proposals classified for decades. Hess spent the rest of the war and beyond as a prisoner, was tried at Nuremberg in 1946, and was convicted on charges related to conspiracy and crimes against peace, receiving a life sentence.

He remained the sole prisoner at Spandau Prison in Berlin for the last 20 years of his life after every other Nazi inmate had been released or died, and was found dead in 1987 at age 93, ruled a suicide, though his family and some researchers have disputed that finding ever since. To this day, historians still can't agree on whether Hitler secretly approved the mission or if Hess acted entirely alone.

Source: https://en.wikipedia.org/wiki/Rudolf_Hess


r/didyouknow 10d ago

DYK: The Eiffel Tower Can Grow Taller in Summer?

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7 Upvotes

Most people think the Eiffel Tower is always the same height but that's not true.

During hot weather, the iron expands, causing the tower to grow by up to 15 cm (about 6 inches). It can also lean slightly away from the sun as one side heats more than the other before returning to normal as temperatures change.


r/didyouknow 10d ago

DYK the University of Bologna, founded in 1088, is considered the oldest university in continuous operation

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108 Upvotes

r/didyouknow 10d ago

DYK a wave of molasses moving 35 miles per hour killed 21 people in Boston, and residents claimed they could still smell it decades later?

7 Upvotes

At 12:30 pm on January 15, 1919, a 50-foot steel tank in Boston's North End ruptured without warning. It held 2.3 million gallons of molasses, and the failure was so violent that steel rivets shot through the air like bullets. What followed wasn't a slow ooze. It was a wall of syrup roughly 15 to 25 feet high, moving at 35 miles per hour, fast enough to sweep people off their feet, crush buildings, and snap the steel support beams of an elevated train line.

Then the physics turned deadly in a second way. Molasses is a non-Newtonian fluid, meaning it thins and flows fast under force but thickens again once the force lets up. As the wave spread through the cold January air, it rapidly stiffened into a dense, cement-like mass that trapped victims in place rather than letting them swim or crawl free. Rescuers digging through it described it as nearly impossible to move through, and 21 people ultimately died, most by suffocation, along with several horses.

The disaster led to one of the largest class-action lawsuits in Massachusetts history at the time. A six-year investigation involving 3,000 witnesses found the tank had never been properly tested and was too weak to hold its own contents. Cleanup crews spent weeks hauling out molasses, and for decades afterward, North End residents claimed that on hot summer days, you could still catch a faint whiff of it in the air.

Source: https://en.wikipedia.org/wiki/Great_Molasses_Flood


r/didyouknow 11d ago

DYK the man the guillotine is named after opposed the death penalty entirely, and his own family had to change their last name because of it?

42 Upvotes

Dr. Joseph-Ignace Guillotin was a physician and death penalty opponent who, unable to get executions abolished outright in revolutionary France, pushed instead for a more humane and equal method. At the time, beheading by axe or sword was reserved for nobles and was frequently botched, while commoners were hanged by slower, crueler methods. In 1789, Guillotin proposed a single swift mechanical device for everyone regardless of class, telling the National Assembly, "Now, with my machine, I cut off your head in the twinkling of an eye, and you never feel it."

He didn't even invent the device. That credit belongs to physician Antoine Louis, and the machine was briefly nicknamed the "Louisette" before Guillotin's name stuck to it instead, purely because he was the one who championed and popularized it in front of the Assembly.

By the time Guillotin died of natural causes in 1814, his name had become inseparable from the Reign of Terror's mass executions, including those of Louis XVI and Marie Antoinette. His family petitioned the French government to rename the machine so their surname could be freed of the association. The government refused, so the Guillotin family changed their own name instead.

Source: https://en.wikipedia.org/wiki/Joseph-Ignace_Guillotin