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There’s a mysterious object from ancient Rome archaeologists still can’t figure out.

  • Roman period dodecahedron
Roman period dodecahedron
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Author Sarah Anne Lloyd
January 31, 2024

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Ancient Rome is one of the most well-studied civilizations on Earth, but there are some aspects of the culture that still puzzle researchers today. Among the oddest mysteries the Romans left behind are small, hollow dodecahedra — 12-sided objects — with no apparent purpose. These dodecahedra are usually about the size of a human fist or a baseball, although the ones that have been found by archaeologists range from 1.5 inches to 4.5 inches tall. Each pane typically contains a differently sized hole between .2 and 1.5 inches wide, and each corner is marked by a spherical stud. The first one was unearthed in 1739, and more than 100 have been discovered since then, mostly around ancient Britain, Gaul, and Roman Germany.

Despite having nearly 300 years to figure it out, archaeologists still aren’t even close to sure what the Gallo-Roman dodecahedra are for, but they do have some wildly disparate ideas. The objects could have been used for a game that’s disappeared from the historical record, for detecting counterfeit coins (some of them were even discovered in coin hoards), or as surveying tools. Names for the zodiac were found on one dodecahedron, leading some to believe that they could be used in astrology. Other ideas include a musical instrument, candle holder, child’s toy, calendar, or a gauge for water pipes.

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London was originally founded during Roman rule.

It’s easy to picture ancient Rome as a Mediterranean locale — after all, it’s where the city of Rome is. But the areas where most of the mysterious dodecahedra were found were all well into northern Europe, stretching all the way to modern-day Britain. There, the Romans founded a walled city called Londinium, although the origin of the name is still unclear. When the Saxons took over — exactly how and when remains, like the dodecahedra, a mystery — they founded a settlement next door called Lundenwic, where London’s West End is today. When the Saxons moved into old Londinium, they renamed it Lundenburgh, which was eventually shortened to London.

Air conditioners were originally invented for printing presses.

  • Willis Carrier with air conditioner he invented
Willis Carrier with air conditioner he invented
Credit: Science History Images/ Alamy Stock Photo
Author Sarah Anne Lloyd
June 5, 2025

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At the turn of the 20th century, Sackett & Wilhelms Lithographing Company, a printing plant in Brooklyn, New York, had a problem: High humidity was causing its paper to wrinkle, swell, and shrink. As a result, the company was dealing with misaligned prints, jammed equipment, and long drying times. So it called on the heating and fans division of Buffalo Forge Company for a solution.

The task fell to mechanical engineer Willis Carrier, who was head of experimental engineering at Buffalo Forge. Because cold air can hold less water vapor, Carrier focused his efforts on cooling the factory down. Buffalo Forge already manufactured heating coil systems — fans that distribute hot air from steam-filled tubes — to heat buildings, so, Carrier reasoned, why not run cold water through the coils instead?

He installed the first modern air conditioning system in 1902, and his experiment was successful — most home air conditioners function on this same basic principle. But the system didn’t operate on the level that Sackett & Wilhelms needed it to. So Carrier got to work on something that could actually meet the needs of a large factory, and developed the first spray type air conditioner, a large enclosure filled with water nozzles that could cool hot air before sending it back into the factory. The cool air, even though it came from a wet environment, could hold less water, so it successfully reduced the overall humidity.

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The ice lobby almost killed ice machines.

When Florida physician and scientist John Gorrie patented a groundbreaking ice machine in 1851, the ice industry that shipped ice to the Southern United States moved to quash it, attacking Gorrie in the press and sowing distrust of the new technology. The public ultimately embraced the ice machine after the Civil War disrupted traditional ice delivery. But Gorrie, who died before the Civil War started, wasn’t trying to make iced tea — he was trying to keep yellow fever patients comfortable by chilling the air.

A Little Ice Age occurred between the 14th and 19th centuries.

  • Winter scene during Little Ice Age, 1787
Winter scene during Little Ice Age, 1787
Credit: Science History Images/ Alamy Stock Photo
Author Rachel Gresh
January 30, 2024

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Saber-toothed tigers and woolly mammoths weren’t roaming the Earth during the last ice age — Leonardo da Vinci and Michelangelo were. A period of global cooling, known as the “Little Ice Age,” spanned the late Middle Ages through the Renaissance era, ending around the dawn of the Industrial Revolution in the mid-1800s. Some locations cooled down more than others, including northern Europe and western North America, which experienced temperature fluctuations between 1.8 and 3.6 degrees Fahrenheit cooler than the thousand-year averages for those regions. 

This drastic change in climate had several possible causes. One leading theory points to a decrease in sunspot activity, which caused less solar radiation to reach Earth’s surface. Significant changes in atmospheric patterns also might have contributed to cooler temperatures in some regions. Or an increase in volcanic eruptions could have been the culprit, causing gas and ash to spew into the atmosphere, cooling the Earth. Some experts suggest it was a combination of all these things. Researchers at University College London believe the temperature drop was exacerbated by an entirely different issue: the depopulation of the Americas following the arrival of European colonists. Mass warfare and disease caused the deaths of 56 million Indigenous people by 1600. Large areas of once-cultivated land turned into forests, absorbing massive amounts of carbon dioxide and preventing it from reaching the atmosphere to warm the planet.

The impacts of the Little Ice Age were global, causing food shortages in parts of Europe, Asia, and Africa. China’s long-standing Ming dynasty fell in 1644, partially due to agricultural woes. Widespread famine uprooted the regular order of society, and Europe’s medieval feudal system (which relied on peasants growing crops for their lords) collapsed (partly due to climate change, though many other factors contributed), giving way to markets and trade systems. This new way of life led into the 17th-century Age of Enlightenment, when exploration, religion, art, and philosophy transformed European society.

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Londoners once held “frost fairs” on the frozen River Thames.

During the latter part of the Little Ice Age, from around 1600 to 1800, the River Thames often froze over, sometimes for up to two months. During this time, thousands of eager attendees assembled on the Thames for festivals called “frost fairs,” where they participated in winter activities such as ice skating, sledding, and bowling. Nearby pop-up tents housed pubs, barbers, shoemakers, and shops selling tea, gifts, and other goods. Food stands served hearty dishes such as roasted mutton and ox, with gingerbread for dessert. The most famous frost fair occurred during the winter of 1683 to 1684 — dubbed the “Blanket Fair” — during one of the coldest winters London had seen. King Charles II was reportedly in attendance and enjoyed festivities including bull-baiting, coach races, and puppet plays. As the end of the Little Ice Age drew near, the Thames froze less often, and the final frost fair was held in January 1814. 

Some airplanes used to have dance floors.

  • Dance floor on an Air Canada jet in 1972
Dance floor on an Air Canada jet in 1972
Credit: Trinity Mirror/Mirrorpix/ Alamy Stock Photo
Author Timothy Ott
June 5, 2025

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Ah, for the days of the groovy ’70s. While most contemporary airline passengers find their in-flight entertainment choices limited to a menu of movies and TV shows, the “Me Decade” saw airlines go all out with attempts to please customers aboard their brand-new Boeing 747 jumbo jets. Case in point: Air Canada turned the upper deck of its 747 into a 5-mile-high club for transatlantic flights between Toronto and Europe, with music blasting from 8-track tapes as passengers shimmied on a dance floor in lockstep with their reflections on a mirrored wall.

Those who missed out on the Air Canada dance-fest could still find other means for enjoyment among the competition. United Airlines and Qantas Airlines transformed the upper-deck compartments of their 747s into lounges, respectively dubbing them the “Friendship Room” and the “Captain Cook Lounge.” The Singapore Airlines version, known as the “Raffles Lounge,” provided “slumberettes” for those who wanted a nap after a few drinks. American Airlines installed a piano bar in the rear main cabin of its 747 fleet, even if the piano was technically a Wurlitzer electronic organ that proved more durable on bumpy flights. 

Sadly, this era of the party plane was short-lived, as airlines realized that the precious space set aside for socializing could be used to pack in even more paying customers. Air Canada’s dance floor lasted for only about a year, and most other plane lounges and bars were gone by the 1980s, thereby eliminating the in-flight option of doing the Funky Chicken for all but the most determined of passengers.

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Zeppelins represented the peak of luxury for air travelers in the 1930s.

Although the commercial airline industry began seeing a major upswing in popularity by the 1930s, a plane ride could still be a cramped and unsettling experience for those aboard. The rigid airships built by Germany's Luftschiffbau Zeppelin, on the other hand, ensured that passengers were traveling to their destinations in comfort and style. The most celebrated of these zeppelins, the massive Hindenburg, featured a spacious dining room, lounge, and writing room to go with the passenger cabins across the upper deck of its hull. The lower deck contained a bar and a smoking room, the latter a head-scratching choice for a dirigible inflated with flammable hydrogen, even if the room was sealed off and pressurized to keep hydrogen from seeping in. 

Of course, the Hindenburg did burst into flames (for unknown reasons) while attempting to dock in New Jersey in May 1937, but even after the accident, customers continued to request tickets for transatlantic flights on an older airship, the Graf Zeppelin. However, the start of World War II and the funneling of parts toward the war effort ushered an end to the zeppelin's reign as kaiser of the skies, and the general public would have to wait a few more decades before enjoying similar levels of luxury aboard an airplane.

The first known photograph took at least eight hours to capture.

  • Reproduction of the world’s oldest photograph
Reproduction of the world's oldest photograph
Credit: dpa picture alliance archive/ Alamy Stock Photo
Author Sarah Anne Lloyd
May 27, 2025

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In the 1820s, French inventor Nicéphore Niépce was experimenting with using light to create and copy lithographs, and found success with bitumen of Judea, a kind of photosensitive asphalt. After spreading a mixture of the asphalt and lavender oil on a pewter plate and exposing it to sunlight, he found that the parts exposed to light would harden, and the parts that were in shadow would wash away easily.

Niépiece decided to expose one of his plates to a camera obscura — a device that projects real-time (but impermanent) images onto a surface. Using this method, he captured the scene outside his second-story window in 1826. Titled “View From the Window at Le Gras,” it’s now considered the first known photograph.

But because this photographic method, which he called heliography, relied on asphalt hardening, it took a really long time to capture. The exact exposure time of the first known photograph is lost to history, but experts estimate eight hours on the low end. If you ask the University of Texas Harry Ransom Center, the current stewards of the heliograph, it likely took several days. 

The first practical photograph, the daguerreotype, which was exposed onto plates of silver, came along more than a decade later in the late 1830s. It was popular in portraiture and a significant improvement on the heliograph, although it still required its subjects to sit for the better part of a minute, so people had to hold very still. 

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Eastman Kodak invented the first digital camera in 1975.

Digital photography went through some seriously clunky phases before smartphones gave us all high-res cameras in our pockets. (Does anyone remember when they recorded photos onto a floppy disk?) Case in point: The first-ever digital camera, invented by Eastman Kodak in 1975, weighed a whopping 8 pounds, was the size of a toaster, and was powered by 16 AA batteries. The camera recorded up to 30 images to a cassette tape, and the images were extremely low-quality. For context, an iPhone 16 can take 48-megapixel photos, while the first digital camera could manage only .01 megapixels.

The Apollo 11 astronauts signed autographs as life insurance policies.

  • Apollo 11 astronauts
Apollo 11 astronauts
Allstar Picture Library Ltd/ Alamy Stock Photo
Author Bennett Kleinman
January 30, 2024

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The Apollo 11 mission was a dangerous endeavor that put the crew’s lives at risk, a fact not lost on astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins. Aware of the risks ahead, the crew of the historic moon mission signed autographs as a way to provide for their families in case of disaster. At the time, standard life insurance policies were extremely expensive for interstellar missions, and would not have adequately supported the astronauts’ families. So, lacking any traditional protection, the astronauts cleverly realized that there was a market out there for signatures from American heroes such as themselves.

The three men entered quarantine roughly a month ahead of the July 1969 mission to the moon. During their free time, they signed hundreds of autographs known as “covers” — signed envelopes postmarked with important dates, such as the date of the moon landing itself. The covers were delivered to the astronauts’ families, who held onto them in the event that tragedy struck. Thankfully, the Apollo 11 crew returned unharmed, so these “insurance policies” weren’t sold. The crews of Apollo 12 through 16 continued this tradition until 1972, though all of those crafts also returned safely. In the 1990s, covers from the Apollo 11 mission began appearing in memorabilia auctions and commanded incredible value, some selling for tens of thousands of dollars.

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The first American to orbit Earth became a U.S. senator.

John Glenn is an American icon. He first served the country by flying 149 missions during World War II and the Korean War, and in 1959, he was selected to be one of the Mercury Seven, NASA’s inaugural class of astronauts. These men became the first Americans to travel into space in 1961. A year later, Glenn became the first American to orbit the Earth. His accomplishment was met with tremendous fanfare back in New York City, where he was celebrated with a ticker tape parade in March 1962, during which 3,474 tons of confetti were dropped from the skies. Glenn parlayed his success into the political world, representing Ohio in the U.S. Senate from 1974 to 1999. However, he returned to space once again in 1998, becoming the oldest person to do so at the time.

Ben Franklin wrote essays for his brother’s newspaper as a widow named “Silence Dogood.”

  • Ben Franklin in his brother’s print shop
Ben Franklin in his brother's print shop
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Author Michael Nordine
May 27, 2025

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Among all the Founding Fathers, Benjamin Franklin had the most interesting extracurricular activities. Before he studied electricity or invented bifocals, America’s first postmaster general had a habit of writing essays for his brother’s Boston newspaper under the pseudonym “Silence Dogood.” The 16-year-old posed as a widow because the writing he submitted under his own name was rejected by the New-England Courant, which his older brother James published. Silence had much to say about a variety of subjects, with her commentary touching on such subjects as religion and politics, and she was an instant hit with the weekly paper’s readers — she even received marriage proposals.

Fourteen of these essays were published beginning in 1722, but all good things must come to an end. After slipping Silence’s correspondence under the Courant’s door for several months, Franklin eventually revealed his true identity. His brother was none too pleased with this deception, having warned the younger Franklin against growing too vain in the wake of the essays’ warm reception, and the fallout played a part in Franklin’s departure for Philadelphia — the city where he lived for the rest of his life.

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Ben Franklin’s son was a Loyalist.

Not every Franklin was a revolutionary. Among the many families divided by the colonies’ quest for freedom was that of the nation’s most eclectic founding father, as Benjamin Franklin’s only son, William, was a Loyalist who sided with England during the American Revolution. Born in 1730, William was with his father during Franklin’s famous kite experiment and later served as royal governor of New Jersey after George III became king of England. William’s gubernatorial tenure led to the father and son being apart from one another for more than a decade, which was enough time for them to land on opposite sides of the Revolution when it began in 1775. Franklin’s efforts to have William join the cause resulted in not only failure but estrangement. William was jailed during the Revolutionary War for acting as an informant and was released in 1778. Four years later, he left the country for England and lived there in exile for the remainder of his life.

The “D” in D-Day doesn’t really stand for anything.

  • U.S. troops on Omaha Beach
U.S. troops on Omaha Beach
Credit: CBW/ Alamy Stock Photo
Author Kerry Hinton
May 7, 2024

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On June 6, 1944, the largest land, sea, and air invasion in the history of the world took place on the beaches of Normandy, France. It was the first phase of Operation Overlord, an Allied plan to land hundreds of thousands of troops into French enemy territory, then move east and liberate the rest of Nazi-occupied Western Europe. The planners of the operation gave it a simple name: D-Day. But what exactly does the “D” stand for? 

The simplest and most widely cited explanation is that the “D” in D-Day stands for “day,” essentially a code indicating a date to be determined (or concealed from enemy forces). “It simply signifies the day that the invasion will launch and puts all the timetables into play,” Keith Huxen, a historian at the National WWII Museum, told TIME magazine in 2019. Military history also supports this theory. In the field, the U.S. Army began substituting the letters “D” and “H” for “day” and “hour” as early as World War I. The days and hours leading up to or following an operation, meanwhile, were often noted with plus and minus signs, such as “H-2” or “D+3.”

Not everyone has agreed with this interpretation, however. In his book The Facts on File Encyclopedia of Word and Phrase Origins, author Robert Hendrickson wrote that “the French maintain the ‘D’ means ‘disembarkation,’ still others say ‘debarkation,’ and the more poetic insist D-Day is short for ‘day of decision.’” Dwight D. Eisenhower, who served as supreme commander of the Allied forces in Europe during Operation Overlord, added to the confusion with his explanation. War Slang author Paul Dickson noted that in 1964, Eisenhower instructed his executive assistant to answer a letter he received about the meaning of D-Day by stating “that any amphibious operation has a ‘departed date’; therefore the shortened term ‘D-Day’ is used.” In fact, there were multiple “D-Days” during World War II, and other single-letter designations were used as well, such as M-Day for “mobilization.”

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The Allies deceived the Germans ahead of D-Day.

To keep Adolf Hitler from deducing exactly where an attempt to take the beaches of Western Europe would occur, the Allies mounted a series of deception efforts known as Operation Bodyguard. Ruses included the use of double agents to pass along false information and fictitious radio transmissions about troop and supply movements. Two “ghost armies” with inflatable dummy tanks were planted in Scotland to indicate a possible invasion of Norway, as well as in southeast England to suggest a landing at Pas de Calais, almost 200 miles northeast of Omaha Beach. Alan Turing and other cryptologists had previously cracked the Nazis’ Enigma code, allowing them to decode enemy communications that indicated the deception was working. The Allies kept up the charade by dropping dummy paratroopers that played the sounds of gunfire and explosions when they landed. Spies continued to spread information after D-Day, ultimately delaying the arrival of German reinforcements for seven weeks. 

Was the Leaning Tower of Pisa Ever Straight?

  • The leaning tower of Pisa
The leaning tower of Pisa
dra-photos/ iStock
Author Bennett Kleinman
January 30, 2024

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Italy’s Leaning Tower of Pisa lived up to its name right from the start, as it began to tilt early on in the construction process. The foundations were laid on August 9, 1173, but work came to a halt as builders reached the fourth floor in 1178. This was in part because the iconic landmark began leaning slightly atop the muddy soil — which was too soft to begin with and settled unevenly under the tower’s weight — and in part due to an ongoing war between Pisa and nearby city-states. When construction recommenced in 1272, the tower was tipped at a roughly 0.2-degree angle, though the soft ground had compacted enough that work could continue. In order to compensate for the lean, new floors were built with one side taller than the other, thus giving the tower a unique curve, though the structure continued to slowly tilt even further.

Construction of the tower’s bell chamber began in 1360, by which time the tower was tilting at a 1.6-degree angle. The Leaning Tower of Pisa was officially completed in 1372, though it took several centuries for its seven giant bells to be installed. Centuries later those bells were stilled, as experts feared that their repeated movement was contributing to the tower’s increasing tilt. By 1990, the tower leaned 5.5 degrees to the side, necessitating the installation of counterweights. While the Leaning Tower of Pisa was originally designed to stand nearly 197 feet tall, it now only reaches a height of 186 feet at its highest point, and 183 feet at its lowest.

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There are two leaning towers in Bologna, Italy.

Though they lack the same worldwide recognition as the Leaning Tower of Pisa, there are two famous leaning towers in the Italian city of Bologna, too: Asinelli and Garisenda. These local landmarks were constructed between 1109 and 1119, and it’s rumored that they may have been built as part of a competition between local families to showcase their status. The Asinelli Tower stands 318 feet tall, contains 498 steps, and leans a modest 1.3 degrees to the side. Its sister tower, Garisenda, on the other hand, is at risk of collapse, as recent warnings suggest the 154-foot-tall structure could topple at any moment. Garisenda was actually lowered by 20% of its total height back in the 14th century, but still developed a 4-degree lean that puts its integrity in question. Bolognan officials are working to stabilize the popular landmark, which was famously referred to in Dante’s epic poem The Divine Comedy.

The U.S. used potatoes to attack a submarine during World War II.

  • USS O’Bannon in 1942
USS O'Bannon in 1942
Credit: Smudge Whisker/ Alamy Stock Photo
Author Michael Nordine
May 27, 2025

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Starchy vegetables aren’t usually top of mind when thinking of weapons of war, but potatoes played a vital role in a World War II battle — and not by feeding soldiers. Everyone’s favorite tuber took a break from being boiled, mashed, and stuck in a stew on April 5, 1943, when the crew of the USS O’Bannon was alarmed to see a Japanese submarine approaching. According to U.S. Navy Commander Donald J. MacDonald — who wrote that, prior to the incident, “the sea was calm; there was no moon; the night was very dark; the sky was overcast and there were intermittent squalls” — the vessel was first spotted at a distance of 7,000 yards traveling at a speed of 10 or 11 knots.

After initially engaging with depth charges and 20 mm guns, the O’Bannon was eventually close enough to its target for sailors to begin throwing objects at it — including, for lack of a better option, potatoes recovered from their deck lockers. One version of the story suggests the Japanese soldiers on the deck of the submarine, believing the spuds were actually hand grenades, panicked by throwing them both overboard and back at their attackers. Their efforts were for naught: The submarine sank and the Americans were victorious. Because the potatoes used were from Maine, the Maine Potato Growers Association presented the O’Bannon with a plaque “for their ingenuity in using our now proud potato” to sink an enemy vessel. The plaque remained on the ship until it was decommissioned in 1970.

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Three pigeons were awarded military medals during World War II.

Potatoes weren’t the only unusual weapon used by the Allies during the Second World War. There were also White Vision, Winkie, and Tyke, three pigeons who served in the Royal Air Force and received official commendations for their efforts. They were the first creatures to receive the Dickin Medal, which the People’s Dispensary for Sick Animals (PDSA) created to honor animals who aided Britain’s efforts in the war. All three carrier pigeons traveled great distances to deliver lifesaving messages that led to the rescue of ditched aircrews, with Winkie flying some 120 miles to do so. According to the citation on the medals, the pigeons were honored “for delivering a message under exceptionally difficult conditions and so contributing to the rescue of an Air Crew while serving with the RAF.”

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