Archives: Facts

Custom post type for facts

Air conditioners were originally invented for printing presses.

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

Love it?

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.

By the Numbers

Did you know?

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
Credit: Science History Images/ Alamy Stock Photo
Author Rachel Gresh
January 30, 2024

Love it?

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.

By the Numbers

Did you know?

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. 

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

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

Love it?

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. 

By the Numbers

Did you know?

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
Allstar Picture Library Ltd/ Alamy Stock Photo
Author Bennett Kleinman
January 30, 2024

Love it?

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.

By the Numbers

Did you know?

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
Credit: ClassicStock/ Alamy Stock Photo
Author Michael Nordine
May 27, 2025

Love it?

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.

By the Numbers

Did you know?

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
Credit: CBW/ Alamy Stock Photo
Author Kerry Hinton
May 7, 2024

Love it?

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.”

By the Numbers

Did you know?

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
dra-photos/ iStock
Author Bennett Kleinman
January 30, 2024

Love it?

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.

By the Numbers

Did you know?

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.

Egyptian pharaohs had to prove they were fit to lead.

Pharaoh Ramses II
Perseomed/ iStock
Author Darren Orf
January 22, 2024

Love it?

Egyptian pharaohs were seen by their subjects as gods — but sometimes, those “gods” had to prove their worth. This occurred at a jubilee-style celebration meant to reaffirm an aging ruler’s kingship, known as the Heb-Sed or Sed festival. The tradition dates back to the first dynasty of ancient Egypt, around 3000 BCE, and usually took place in the 30th year of a pharaoh’s reign (and every three years after that). The event was filled with sacrifices, crownings, and other lavish displays; the Heb-Sed of Amenhotep III, for instance, featured the construction of temples and colossal sculptures all along the Nile valley. But the main event was a footrace run by the pharaoh — dressed in a kilt with an attached animal tail — to demonstrate their physical fitness. 

According to Egyptologists, ancient Egyptians likely related the health of their ruler to the overall health and virility of the kingdom. If a pharaoh couldn’t complete the race, it signaled that it was time to make way for a younger, healthier leader. Of course, thousands of years before modern medicine, 30 years was a long lifespan, and only a small percentage of pharaohs lived long enough to celebrate a Heb-Sed. Not all of them passed the test: Although a simple footrace may seem like a relatively easy method for reaffirming your reign, pharaohs were not nearly as svelte or athletic as hieroglyphics and ancient carvings would have us believe. Many kings and queens were plagued with various maladies caused by inbreeding, as well as obesity: A pharaoh’s diet, often filled with beer, wine, bread, and honey, contained an awful lot of sugar.

By the Numbers

Did you know?

King Tut wasn’t a particularly important pharaoh.

Ask the average person to name some ancient Egyptian pharaohs and Tutankhamun, known more commonly as King Tut, would likely make the list. His name became famous when his remarkably well-preserved tomb was discovered in the 1920s, but Tutankhamun was arguably one of the least memorable leaders of his era. Becoming pharaoh at around 9 years old, he reigned for only a decade before dying mysteriously. His most notable accomplishment was reversing the monotheistic inklings of his father, Akhenaten, and returning the kingdom to its old pantheon of gods. Little else is known of his rule, however. Scholars and Egyptologists theorize that Tutankhamun may have been a puppet of royal advisers and priests, and thus his reign left little mark on Egyptian history. 

The Salem witch trials weren’t actually finished until recently.

Elizabeth Johnson Jr. witch trial
Pictorial Press Ltd/ Alamy Stock Photo
Author Rachel Gresh
January 18, 2024

Love it?

In the woods of Salem, Massachusetts, there is a summit called Gallows Hill, where the darkest days of the town’s history occurred. Here, nearly 20 people lost their lives by execution after being accused of witchcraft during the infamous Salem witch hunts of 1692 and 1693. One of the accused, a 22-year-old woman named Elizabeth Johnson Jr., was pardoned from execution but not cleared of charges until 2022, leaving her name sullied for more than three centuries.

Toward the end of the witch-hunting frenzy, the governor began sparing the accused from execution, including Johnson. In 1711, colonial Massachusetts lawmakers passed an act that reversed the witchcraft convictions of 22 individuals, but Johnson’s name wasn’t among them. She petitioned to have hers added, and it is unclear why she was left out. Legislation clearing additional names continued to trickle in over the decades, as recently as 1957 and 2001, but Johnson was never listed. Finally, in 2021, students at North Andover Middle School (in the town adjacent to Salem) learned about the matter in class and urged their teacher to take action. The teacher alerted state Senator Diana DiZoglio, who sponsored an amendment to clear Johnson’s name. On May 26, 2022, 329 years after she was wrongly accused, Elizabeth Johnson Jr. was finally exonerated, making her the last known person convicted of witchcraft in Salem to be cleared of the charges. 

By the Numbers

Did you know?

One of New England’s “witch tests” involved baking a cake.

As mass paranoia swept Europe and the American colonies, tests were devised to reveal who was really a “witch.” Unfortunately, these tests were markedly unfair, and most were unpassable, resulting in the death or conviction of many innocent people — rarely was anyone cleared by these tests. One of the most peculiar tests was the “witch cake,” which involved baking a cake with rye meal, ashes, and the urine of the accused witch’s “victim.” The cake was then fed to a dog (at the time, dogs were associated with the devil), and if the dog displayed the same symptoms as the “victim,” the accused was confirmed to be a witch. The dog would allegedly even point to the guilty “witch.” Inspired by a similar English practice for revealing witches, the test was created by Salem resident Mary Sibley. Though Sibley had hoped to help her neighbors and their bewitched children, the test only fueled the panic. Eventually, baking the cake was considered by some to be an act of witchcraft itself. 

Thomas Jefferson and John Adams stole a piece of Shakespeare’s chair.

Shakespeare's wooden armchair
Credit: Andreas von Einsiedel/ Alamy Stock Photo
Author Sarah Anne Lloyd
May 22, 2025

Love it?

In April 1786, Thomas Jefferson and John Adams, who were close friends despite their political differences, took a horse and carriage on a weeklong tour of England. Both were great admirers of William Shakespeare, and one of their first stops was the Bard’s hometown of Stratford-upon-Avon. According to Abigail Adams, Jefferson was so moved that he kissed the ground of the house where Shakespeare was born — although he also complained about the entrance fees, and Adams called the house “small and mean.”

Among the many relics at the house was Shakespeare’s own chair, where the poet and playwright supposedly sat and wrote his great works. When the founding fathers left, they sliced off a piece of the chair to take home as a souvenir. (A chip of Shakespeare’s chair — which may or may not be the one that Jefferson and Adams shaved — is currently on display at Monticello.)

In their defense, this was a fairly normal thing to do at the time. As Adams wrote in his diary, “We cutt [sic] off a Chip according to the Custom.” Before the ubiquity of gift shops and commemorative snow globes, tourists would scavenge for whatever souvenirs they could find, often pilfering little bits of significant objects or buildings. In fact, Jefferson’s own gravestone had to be removed and replaced because too many visitors wanted to take a piece home.

By the Numbers

Did you know?

Thomas Jefferson and John Adams were bitter rivals and close friends.

Despite their well-known political differences, Jefferson and Adams had quite a genuine affection for each other, which became even more apparent after politics brought their friendship to a temporary end. The pair stopped corresponding after Adams made some unwelcome political appointments right before Jefferson’s presidency began — Jefferson told Abigail Adams that he spent some time “brooding over it.” 

When Jefferson’s presidency ended in 1809, founding father Benjamin Rush made it his mission to restore the friendship. It took two years, but eventually one of Jefferson’s neighbors overheard Adams saying, “I always loved Jefferson, and still love him.” Jefferson echoed the sentiment, telling Rush, “I only needed this [knowledge] to revive towards him all the affections of the most cordial moments of our lives.” Rush convinced Adams to reopen communication, and the former friends spent the last 15 years of their lives in doting correspondence, before dying on the same day.

x