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Red is the most complex color in the visible spectrum. In one moment, red can conjure images of war and bloodshed, and in another, transform into a symbol for passionate love and affection. Humans dedicated Earth’s red rocky neighbor to the Roman god of war, while the ruddy hues of roses show a deep devotion to someone we love. But the color red is even more important in the human psyche than you might realize, and these six facts show why this particular slice of the rainbow holds such a strong psychological sway over us.

triangular prism breaks light into spectral colors.
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Red Is at the Far End of the Visible Spectrum

The electromagnetic spectrum contains a wide range of radiation, each defined by the size of its wavelength. On the extremely small wavelength end, there are gamma rays from supernovae, pulsars, and neutron stars, and on the other end of the spectrum, radio waves — perfect for communication, as the large waves easily travel through the atmosphere. Color is a small slice of electromagnetic radiation, and is known specifically as the “visible spectrum.” Within this spectrum, each color (red, orange, yellow, green, blue, indigo, violet) is also represented by a wavelength range. Violet, at around 380 nanometers, is the shortest wavelength. At 700 nanometers, red is the longest wavelength the human eye can perceive.

Just adjacent to this wavelength is infrared, a type of radiation we cannot perceive. However, just because we can’t see it doesn’t mean it’s not important. Infrared is absolutely vital to humanity’s exploration of space, because the long wavelengths can pass more freely through cosmic dust. This allows astronomers using special telescopes to peer back billions of years into the very early beginnings of the universe.

Group of flags of many different nations against blue sky.
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Red Is the Most Common Color on National Flags

Purple is the least common color found on national flags (gracing only the banner of the Caribbean country Dominica), while red is the opposite, and can be found on a whopping 74% of flags, according to Guinness World Records. Around 50% of these flags use red to represent the blood of those who fought for the country, extolling the virtues of bravery and valor. This includes the U.S. flag, with the red standing for “hardiness and valor.” Meanwhile, when red is considered alongside vexillology’s second-favorite color, blue, only nine countries in the world (out of 196 total) have flags without red and/or blue in them.

Cave painting of a hand stencil.
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The Oldest Cave Painting in Europe Is a Red Dot

In 2012, scientists discovered that a painted red dot in a cave in northern Spain was likely the oldest cave painting found in Europe — it may be more than 40,000 years old. Red is one of the world’s oldest pigments, and is the primary color found in some of the world’s most famous cave paintings. That’s because our ancient ancestors discovered the long-lasting properties of natural clay known as ochre (pronounced OAK-er). Colored by hematite, a reddish material that contains oxidized iron, ochre withstands the ravages of time well. It can also be easily found in caves and valleys, which is why it is one of the primary mediums for humanity’s earliest works of art.

Couple wearing red behind heart shaped balloon.
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Finding the Color Red Attractive May Be a Part of Human Biology

Red means many things, and sometimes those meanings are contradictory — love and war, rage and lust, etc. Anthropologists concur that the color has been socially linked with lust dating back to humanity’s beginnings. Evidence suggests that red ochre was commonly used during fertility rituals in hunter-gatherer communities, often painted onto a woman’s body and face. Consider the Valentine’s Day obsession with red, and the throughline of sexualizing the color is obvious.

But some scientists think that there might be more to it than our own social conceptions. A 2008 study theorized that humans, much like closely related primates, subtly perceive the color red as a mating signal. While this is more obvious in primates such as baboons, who blush red as heightened estrogen levels increase blood flow near the skin, humans undergo a similar red-hued transformation, often becoming flush in the face or neck during sexual excitement. Some scientists have found a “romantic red hypothesis” in case studies determining attractiveness, with men and women both rating someone more attractive if they’re wearing red. However, other studies found negligible increases in attractiveness, or even a negative correlation, so the jury is still out as to whether humans are really hard-wired to be particularly turned on by red.

Blood drawn from a patient with Serum separate in the chemistry laboratory.
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Iron Is Why Human Blood Is Red

Hemoglobin is a vital part of the human body, being the protein responsible for delivering oxygen to tissues, and for turning our blood red. That’s because hemoglobin contains a red-hued compound known as “heme,” with an iron atom that bonds with oxygen. Hemoglobin bound to oxygen absorbs blue-green light and thus reflects back bright red. This also explains why deoxygenated blood is a much darker red (“blue” veins are actually an optical illusion). Most mammals, fishes, reptiles, amphibians, and birds have red blood due to hemoglobin, but there are some exceptions found throughout the animal kingdom. For example, horseshoe crab blood, a vital ingredient for many vaccines, is actually blue because it contains hemocyanin, which uses a copper atom instead of iron for binding oxygen, and thus reflects light differently. Unlike our red blood cells, deoxygenated horseshoe crab blood is actually colorless rather than a deeper hue of blue.

beautiful baby looking at infinity.
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The First Color Humans Can Perceive Is Red

After only a few weeks of life, babies begin to distinguish their first color (after white and black) — red. Humans perceive color thanks to three types of cones found in our eyes, each tuned to short (blue), medium (green), and long (red) wavelengths. Although cones perceive color from birth, it takes time for the human brain to make sense of those inputs. Because an infant’s vision is blurry during the first few weeks of life, red is the only color capable of being captured by the retina when viewed around 12 inches from a baby’s face. At the two-month mark, babies can begin to distinguish between reds and greens, followed closely by yellows and blues a few weeks later.

Darren Orf
Writer

Darren Orf lives in Portland, has a cat, and writes about all things science and climate. You can find his previous work at Popular Mechanics, Inverse, Gizmodo, and Paste, among others.

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Time capsules bring history to the present and provide future generations insight into what life was like in the past. In 2122, if one were to dig up a time capsule that encompassed 2020 to 2022, it would undoubtedly tell the story of the COVID-19 pandemic, perhaps with a face mask, a home testing kit, and a computer fully equipped with Zoom. Oh, and let’s not forget a recipe for sourdough starter and a phone with TikTok installed.

Time capsules have been around for centuries, and some of the oldest have included items that date back to the 1600s. Here are a few of the most fascinating time capsules in history.

A silver plaque inscribed by Paul Revere that was contained in a time capsule.
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Paul Revere and Samuel Adams Time Capsule, 1795–2015

On July 4, 1795, American patriot Paul Revere, Massachusetts Governor Samuel Adams, and Revolutionary War Colonel William Scollay created what is considered the world’s oldest known time capsule. At a ceremony marking the completion of the Massachusetts State House, they placed items underneath the cornerstone of the building. It remained there until 1855, when it was dug up during emergency repairs. Then-Governor Henry Gardner added more objects to the collection, and the capsule was eventually reburied. During repairs in 2014, the time capsule was retrieved again, and its contents were finally revealed. It included coins minted as early as 1667, an engraved silver plaque, and a medal depicting George Washington. Following an exhibit of the artifacts at Boston’s Museum of Fine Arts, the time capsule was replaced in the state house.

Bob Casey viewing contents of the Centennial Safe.
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The Century Safe, 1876–1976

In his book Time Capsules: A Cultural History, William E. Jarvis identifies the Century Safe as the first modern time capsule, due to its specified reopening date. Magazine publisher Anna Deihm chose the items — including photos of government leaders and inkstands belonging to famous writers — as part of the 1876 Philadelphia Centennial Exposition. She enclosed them in a 5-foot-tall iron safe, which she gave to the U.S. House of Representatives to reopen in 1976. The huge, heavy box ended up stored on the Capitol’s east portico for the next eight decades. When the time came to open it during the nation’s bicentennial, no one remembered where the keys were, and a locksmith had to crack it open.

President of the World's Fair standing over the Westinghouse Time Capsule as it is lowered.
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Westinghouse Time Capsule, 1938–6938

George E. Pendray coined the phrase “time capsule” when he coordinated the Westinghouse Time Capsule at the 1939 New York World’s Fair. The 7.5-foot-long, tube-shaped container was made of the company’s new copper alloy, Cupaloy, designed to withstand burial for 5,000 years. Pendray solicited suggestions for its contents from leading thinkers, and ended up with a mix meant to represent life in the 1930s, ranging from a can opener and textiles to seeds. Microfilms of written material and newsreels completed the contents. The capsule was buried on September 23, 1938, on the World’s Fair grounds, where it remains today. Westinghouse added a second time capsule to the vault during the 1964 World’s Fair. The items are intended to be dug up around 6938.

Dr. Thornwell Jacob seals the last time capsule to be placed in the Crypt of Civilization.
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Crypt of Civilization, 1940–8113

In 1936, inspired by the discoveries of ancient Egyptian tombs in the 1920s, Oglethorpe University president Thornwell Jacobs imagined a collection of items that would show future archaeologists life in the 20th century. He stipulated that this “crypt of civilization” should be opened in the year 8113, a date he determined by doubling the number of years between what was believed to be the start of the Egyptian calendar (4241 BCE) and 1936, so that his collection would represent the midpoint of world history. Over three years, Jacobs amassed donated items as diverse as dental floss, beer, and an original script of Gone With the Wind, and built an impenetrable chamber on the university’s Georgia campus in which to store them. In May 1940, the crypt was sealed behind a steel door for (almost) all eternity.

Time Capsule on the Castle Grounds in Osaka, Japan.
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Expo ’70 Time Capsule, 1970–6970

The time capsule craze was still going strong in 1970 when the Panasonic Corporation and Mainichi Newspapers assembled two identical capsules during the Japan World Exposition in 1970. The first will remain sealed until 6970, while the second was reopened for inspection in 2000 and is scheduled for regular maintenance every 100 years. Organizers included an extensive selection of Japanese cultural objects, literature, and modern inventions in two large steel cylinders, which were lowered by crane into the ground next to Osaka Castle in January 1971.

A Millennium Vault which was sealed until the year 3000 containing various 20th century items.
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Millennium Vault, 2000–3000

Along with the fear of malfunctioning computers, Y2K brought on a wave of interest in time capsules commemorating the 20th century. Organizers in Surrey, U.K., assembled an especially nostalgic collection of objects for Europe’s — and the world’s — largest time capsule vault on the grounds of Guildford Castle. Behind the brick façade, scheduled to be reopened in the year 3000, are a rust-proof Cooper Mini, a Rolls Royce hood ornament, a Sony Walkman, a life-size photograph of World War II-era singer Vera Lynn, and other artifacts. The U.S. had its own — and much smaller — millennium time capsule containing a chunk of the Berlin Wall, Ray Charles’ sunglasses, a Twinkie, and more, due for unearthing in 2100.

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The artist Wassily Kandinsky described orange as “red brought closer to humanity” in his 1912 book, Concerning the Spiritual in Art. While the color has had some famous champions — Vincent Van Gogh made liberal use of it, as did Paul Gauguin — it’s also pretty controversial. For some, it symbolizes joy and happiness, while others find it overwhelming.

Whether you’re pro-orange, anti-orange, or orange-neutral, we see it every day. It’s the color of traffic cones, autumn leaves, the fruit of the same name, and so much more. You know that nothing rhymes with the word (supposedly), but what else do you know about the shade itself? These six facts may deepen your understanding of the hue.

Fresh sliced oranges on a wooden board.
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The Color Is Named After the Fruit

The word “orange” refers to both a citrus fruit and the color of said fruit, so which usage came first? The color isn’t exclusive to the fruit, of course, but the term did come from it. The first use of “orange” as a color in English dates back to the 15th century, and was derived from pomme d’orenge, the French word for the citrus.

“Orange” started appearing in written English works as a color around the 16th century. Before that, English speakers just described it as “yellow-red.” Renowned 14th-century author Geoffrey Chaucer didn’t even have a singular word to describe a fox in his famous work The Canterbury Tales: “His colour was bitwixe yelow and reed [sic].”

Traffic cones on road with electronic arrow redirecting traffic.
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There’s Science Behind “Safety Orange”

You probably see safety orange, also known as OSHA orange, hunter orange, or blaze orange, every day on traffic cones, high-visibility clothing, and road signs. The color first started appearing in technical manuals in the 1950s, but it gained some extra scientific rigor in 1959 when the Massachusetts Division of Fisheries and Game, along with the U.S. military, studied it as a color for high-visibility gear.

More than 500 study participants viewed various bright colors under different lighting conditions. Reds tended to disappear under dark lights. Yellow paled to an off-white at certain hours. Orange was the most readily visible to the highest number of people in the majority of lighting conditions — and the least likely to be mistaken for a natural phenomenon, like a tree or an animal.

Most states (starting with Massachusetts) now mandate that hunters wear this color, or sometimes hunter pink, and it’s the standard color for anything you want to be hyper-visible.

Vegetables and fruit with beta carotene.
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Plants Get Their Orange Hue From Carotene

Bright-orange carrots lend their name to the substance carotene, which gives the vegetable its vibrant hue. While carrots are especially rich in carotene, the substance is found in all sorts of orange plants, like yams — and even plants that aren’t always orange.

Green trees are green because of chlorophyll, a green pigment that helps plants process energy. But when leaves start to die in autumn, the chlorophyll degrades, letting other pigments like carotene and related compounds shine through. It’s also why oranges start out green but turn, well, orange.

Burning wood at night.
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There Are Multiple Reasons for Orange Fire

The color of the glow from a fire depends on the temperature of the flame. Red fire is cooler in temperature, followed by orange, and then white, which is why the colors on the edge of a fire change as it hits the air. This applies to all hot things, not just fire — like red lava. But there’s another reason the fire in your hearth or campsite might be a certain color. When wood burns, it releases sodium, which burns orange. If you see little blue streaks, that’s from carbon and hydrogen.

Tiger picking up a scent.
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Tigers’ Orange Fur Provides Unlikely Camouflage

Like people, tigers hunt in orange — they just have less of a choice in the matter. The good news (for them) is that they hunt a lot of colorblind prey, like deer and other ungulates, for whom the tigers actually appear to be the same color as the foliage around them. Their stripes, which dissolve into a woodland background, are uniquely suited to movements like stalking prey. A tiger’s target will sense its movement, but won’t actually clock the outline of a tiger, allowing the hunter to follow its prey undetected.

Golden Gate Bridge in San Francisco, California.
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The Golden Gate Bridge’s Orange Color Wasn’t Planned

San Francisco’s Golden Gate Bridge, completed in 1937, has a bright earthy tone dubbed “international orange” — but when construction began in 1933, it was on track to be a boring, standard bridge color like black or silver (although the Navy also suggested yellow and black stripes so that it would be highly visible for ships). Consulting architect Irving Morrow noticed that some of the beams were primed in a reddish-orange color, and made it his personal mission to bring a similar shade to the finished product.

The warm color, he argued, was uniquely suited to San Francisco. It would stand out even on foggy days, and when the sun was out, the hue would pop against the blue sky and water. Such a distinct look would highlight the massive scale and stunning architecture of the bridge.

Morrow made his case to the Department of War, the permitting agency for the bridge, in 1935, and successfully convinced them. Today, the color gets touched up in small segments, since repainting the whole bridge would be a massive undertaking.

Want to replicate the bridge’s tone in your own home? The exact mix is on the bridge’s website.

Sarah Anne Lloyd
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Sarah Anne Lloyd is a freelance writer whose work covers a bit of everything, including politics, design, the environment, and yoga. Her work has appeared in Curbed, the Seattle Times, the Stranger, the Verge, and others.

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For avid readers, libraries are a place of sanctuary. They can unlock a world of imagination, investigation, and learning. Much like the books they hold inside, library buildings can also be wondrous creations, boasting magnificent and creative architecture. Others are noteworthy for their quirky designs or the innovative methods they use to inspire their communities to read. Take a journey to six of the most unusual libraries in the world.

Indonesian children sorting through books from a book shelf on a horse.
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Biblioburro (Colombia)

Luis Soriano, a teacher from the rural northern Colombia town of La Gloria, was determined to give his students access to books, so he set up an unusual library called Biblioburro. Soriano owned two donkeys, whom he renamed Alfa and Beto — combined, the names form the Spanish word for “alphabet.” Loading the donkeys with about 70 books from his own bookshelves, Soriano saddled up and rode them to local elementary schools to read students stories. Twenty-five years later, Soriano’s book collection has grown considerably, and he is still spreading his love of reading. Even a riding accident that left him with a prosthetic leg hasn’t stopped this determined educator from inspiring young Colombian children with the joy of reading.

Floating library Epos in the port of Bergen, Norway.
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Epos Library Ship (Norway)

Until the pandemic shut down operations in 2020, a library ship called Epos sailed through Norway’s many fjords to deliver books to fjordside communities. Built in 1963, it superseded two earlier ships that had been in service since 1959. Some of the country’s more isolated places are easier to reach by boat than by road, and this service meant that villagers had access to reading material, particularly during the winter months. Epos carried approximately 6,000 books and visited 250 villages two times per year. Given the unusual circumstances, one qualification for taking a job as one of its librarians was not suffering from seasickness. Similar “libraries” exist in Chile’s Chiloé Archipelago and on the Nam Khong River in Laos. (In 2023, the Epos was relaunched as a traveling bookstore and center for literary events.)

The librarian Joseph Otieno unloads his camels.
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Camel Library (Kenya)

In rural northeast Kenya, camels, nicknamed “ships of the desert,” once carried unusual cargo as part of a Kenya National Library Service initiative. Concerned by poor literacy rates and lack of access to reading materials in and around the town of Garissa, the local government adopted a novel approach. Camels are well-suited to the harsh terrain and hot summer temperatures in the region, so they were an ideal choice to transport hundreds of books along with a tent and reading mat to the area’s nomadic communities. Eventually, after many years of success, improvements to the local road infrastructure meant that the camel library could be phased out and replaced by motorbikes.

Lire a la Plage in Le Havre, France.
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Lire à la Plage (France)

Each summer, Lire à la Plage (“Reading at the Beach”) brings the library to more than a dozen of Normandy’s coastal resorts. The colorful beach huts, umbrellas, and deck chairs are easy to spot, and though people are not allowed to take books away from the beach, the librarians are happy to make a note that you’re coming back the following day, mark your place, and put it aside for you. The program has been running in France since 2005, but similar reading initiatives have spread as far as Australia’s Coogee Beach, the tourist resort town of Albena on Bulgaria’s Black Sea coast, and Tel Aviv, Israel, a city that had previously installed books at bus stops.

A photograph showing books in the Chained Library at Hereford Cathedral in England.
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Chained Libraries (England)

The practice of chaining reference books to library shelves was common in medieval times. Though it mostly ended in the 18th century, there are around a dozen chained collections that still exist in England. The oldest is the Francis Trigge Chained Library, founded in 1598 at St Wulfram’s Church in Grantham, Lincolnshire. The largest chained library in England, meanwhile, is located inside Hereford Cathedral; its oldest book dates back to the eighth century. Another chained library at Wimborne Minster in Dorset dates from 1686. The books in these libraries were chained to the shelves to prevent theft, which is perhaps preferable to the methods used in Marsh’s Library in Dublin, Ireland, where three wire alcoves were installed in the 1770s. If readers wanted to look at some of the library’s rarest books, they’d be locked up in these cages so they couldn’t walk off with them.

A boy reading a book during a visit to the "neighborhood library" in the financial district of Manila.
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Nanie’s Reading Club (The Philippines)

In 2000, a Filipino man named Hernando “Nanie” Guanlao was looking for a way to honor his beloved parents, who had recently passed away. While some people might pay for a plaque on a park bench or make a charitable donation, Guanlao had a more unusual idea: He decided to set up a library outside his home to thank his parents for instilling in him a lifelong passion for reading. Guanlao initially gathered up his own modest collection of books and placed them on the sidewalk for neighbors to borrow. When his neighbors returned them, they also brought some of their own books, and the collection grew rapidly. Two decades later, Nanie’s Reading Club is more popular than ever, and every inch of space in his home, inside and out, is covered with books. There’s no charge to borrow one, and Nanie even ventures out into other Manila districts on a specially adapted “book bike” to spread his love of reading further.

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Interesting Facts writers have been seen in Popular Mechanics, Mental Floss, A+E Networks, and more. They’re fascinated by history, science, food, culture, and the world around them.

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The average human lifespan has increased significantly over the last century, but we still don’t measure up to some of the longest-living plant and animal species on Earth. Sponges that sit at the bottom of the ocean for millennia, hardy trees that live where few other plants can survive, and centuries-old behemoths of the deep sea are just a few of these masters of longevity. Read on for more about six creatures that stretch the limits of lifespans on Earth.

Greenland shark near the ocean ground.
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Greenland Shark

For decades, scientists suspected that Greenland sharks (Somniosus microcephalus) had long lifespans based on their slow rate of growth, but evidence was lacking until a team of Danish researchers devised a new way to gauge their age in 2016. They realized that a protein in the sharks’ eyes formed at birth and didn’t degrade over time. The researchers carbon-dated the proteins, and found that the largest of the 28 sharks they studied, a 16-foot female, was likely between 272 and 512 years old — making Greenland sharks the longest-living vertebrates on Earth. Their hyper-extended lives may be due to their slow metabolism, which helps them survive the cold Arctic waters year-round. In fact, Greenland sharks may not even reach maturity until they’re over a century old.

A Bowhead arctic whale close to ocean surface, chasing after fish.
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Bowhead Whale

Bowhead whales (Balaena mysticetus), an Arctic species that can average 60 feet in length and weigh 60 tons, were hunted for centuries for their oil and baleen. Ironically, that practice has offered clues to their longevity. In the 1980s and ’90s, subsistence hunters in Alaska found, embedded in animals they harvested, old stone and metal harpoon points that were estimated to have been in use from the 1860s to 1890s and even earlier — indicating that the whales were at least a century old. The sequencing of the bowhead whale genome in 2015 revealed genetic mutations that might contribute to their resistance to cancer and lifespans of 200 years or more, confirming Native Alaskans’ observations that the whales could “live two human lifetimes.” Most scientists agree that bowhead whales are the longest-living mammals on Earth.

A glass sponge making a rigid lattice of sillicate spicules extracted from seawater.
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Glass Sponge

These poetically named marine invertebrates don’t look much like your typical kitchen scrubber. Glass sponges have skeletons composed of geometric granules of silica that grow into elongated spears or vase-like shapes. A deep-sea glass sponge with the scientific name Monorhaphis chuni grows almost 10 feet long, forming the largest animal-made silicate structure on Earth, according to a 2012 study. And if that rather specific superlative isn’t impressive enough, M. chuni can live to be 11,000 years old, one of the oldest creatures on the planet. Scientists have analyzed M. chuni skeletons for clues about environmental conditions in the distant past, because — much like tree rings — the structures reveal the chemical signatures of their surroundings over time. Researchers are now using the data to build models of future climate changes.

Bucket full of fresh quahogs.
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Ocean Quahog

The thick shells of ocean quahogs, a type of clam, litter Atlantic beaches from North Carolina to Newfoundland — and beachcombers might not realize they’re stepping on one of Earth’s longest-living species. These edible bivalves (Arctica islandica) mature slowly, with their progress shown in growth ridges on their shells. By counting these ridges, scientists from Bangor University in Wales discovered that an ocean quahog they harvested from Icelandic waters in 2006 was 507 years old; they named it “Ming” after the Chinese dynasty that ruled at the time of its birth. Ming subsequently earned a Guinness World Record as the oldest non-colonial animal ever (meaning the creatures live alone and not in colonies, as glass sponges do).

Wildlife Aldabra giant tortoise (Aldabrachelys gigantea) on the turtle island.
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Seychelles Giant Tortoise

He’s big, he’s slow, and he celebrated his 190th birthday in 2022. Jonathan the Seychelles giant tortoise has lived for more than a century at the governor’s residence on St. Helena, a small island in the South Atlantic, along with three other younger tortoises. Seychelles giant tortoises are thought to live well past 100 or even 200 years old, though their ages are difficult to pin down because they usually outlive the people studying them. Jonathan’s age was determined from an 1882 letter mentioning his arrival at St. Helena as a fully grown tortoise, suggesting that he was already at least 50 years old at that point. While Jonathan does hold the Guinness World Record as the oldest known land animal, his veterinarian told The Washington Post that fame doesn’t faze him: “While wars, famines, plagues, kings and queens, and even nations have come and gone, he has pottered on, totally oblivious to the passage of time.”

View of a Bristlecone Pine.
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Bristlecone Pine

When it comes to longevity, ambulatory animals have nothing on plants. Several species of trees can live for a couple thousand years, but the oldest trees on Earth are Great Basin bristlecone pines (Pinus longaeva) — a rare species found only in arid, high elevation areas of California, Nevada, and Utah. Shaped by constant winds into twisted, gnarled silhouettes, bristlecone pines have been shown to survive for at least 4,000 years. In 1964, a geographer sampled a bristlecone pine nicknamed Prometheus and discovered 4,862 growth rings in its trunk before it was cut down, although the conditions in which the tree grew were so harsh it may actually have been about 4,900 years old (many trees typically form around a ring a year). The oldest living specimen is a tree dubbed Methuselah in California’s Inyo National Forest, estimated to be about 5,000 years old. To protect it from human-caused damage, there are no signs marking its location.

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Interesting Facts writers have been seen in Popular Mechanics, Mental Floss, A+E Networks, and more. They’re fascinated by history, science, food, culture, and the world around them.

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Medicine has come a long way since the four humors and miasma theory. Today’s medical advances incorporate futuristic technology like human-robot interfaces, lab-grown cells, and interspecies transplantation to help patients live healthier and more rewarding lives. Here are a few recent breakthroughs.

Healthcare worker with protective equipment performs coronavirus swab.
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A Bionic Nose to Smell the Roses

More than 20% of the general population may experience the loss of their sense of smell, known as anosmia, at some point in their lives. Anosmia can be caused by an injury or disease, and it’s a common symptom of COVID-19. Now, a neuroprosthetic nose being developed by researchers at Virginia Commonwealth University’s Smell and Taste Disorders Center could help people with long-term anosmia by restoring their sense of smell. The device works by transforming odor into radio waves and transmitting the signal directly to the brain, bypassing the olfactory nerves. The concept is similar to a cochlear implant: Users wear a small sensor that picks up an aroma in the air and transmits it to a tiny processor, which turns it into a specific frequency and sends it to a receiver implanted in the user’s brain. The receiver then sends the signal to electrodes that stimulate the brain as if the user were smelling the odor. If the final product makes it to market, this bionic nose may one day help people smell again.

View of a 3D printed heart.
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3D-Printed Hearts to Help Doctors Test Treatments

Everybody’s heart is different, and the tricky part of treating heart disease is figuring out which treatments are best for a specific patient. Over the past few years, researchers at the Massachusetts Institute of Technology have been developing 3D-printed hearts to help cardiologists save lives. First, specialists take images of a patient’s heart and then convert them into a digital model. They can 3D-print the model using a flexible ink, creating a malleable ticker that is anatomically and mechanically identical to the patient’s. Doctors can even 3D-print arteries and valves and manipulate the parts to test various treatments for the patient’s condition. Though they’re not meant for transplanting, the hearts have the potential to help doctors quickly tailor treatments (such as choosing the right kind of synthetic valve to implant) to individual people.

Human eye anatomy showing blood vessels and peripheral vessels.
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Lab-Grown Retinal Cells That Act Like the Real Thing

Researchers supported by the National Eye Institute had a recent breakthrough in the fight against vision loss. They not only grew real human retinal cells in their lab; they were able to coax the cells into forming synapses, the connections that allow the retina to capture images and eventually send them to the brain. In their experiment, the scientists grew stem cells into the different cells that make up the eye’s retina, such as light-sensing rods and cones, which eventually formed rudimentary organoids (tiny tissue cultures derived from stem cells). Then they broke them up into individual cells, severing any synapses that had formed, and injected the cells with a molecule that would show whether new synapses grew. After just 20 days, the different types of cells had formed the circuits and were “talking” with one another. That is raising hopes for restoring people’s sight through transplantation. Retinal cells aren’t the only organoids that researchers have been able to create from human stem cells, though: Liver, bone, skin, muscle, and even brain organoids have been grown in labs.

Close-up of a robot hand.
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Robotic Hands With the Sense of Touch

Robotic prostheses for people who have lost their arms or hands have been around for over a decade; wearers can control the devices by using muscles in their shoulders or just by thinking about specific movements. But a common complaint among users is that the prostheses don’t feel natural. Researchers at the University of Pittsburgh’s Rehab Neural Engineering Labs recently succeeded in creating prosthetic hands with sensors that “touch.” When a person grasps an object with the sensor-enabled hand, it transmits the sensation of touch to the wearer’s nervous system via an implanted receiver near the spine. People who have participated in experimental studies report a tingling feeling similar to the natural sense of touch. Researchers believe that the sensors will help users with robotic hands perform actions more efficiently, and the bionic body parts may also reduce phantom pain associated with limb loss.

A hand holding a chemistry test-tube with asolution in a bio-chemistry DNA genetic research lab.
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Curing Genetic Conditions With Gene Therapy

Since the development in 2012 of CRISPR-Cas9, a molecular tool that can fix faulty DNA by activating or deactivating genes or removing them altogether, scientists have been trying to use the tool to cure genetic diseases. Through much trial and error, as well as controversy, a handful of treatments based on gene therapy have now been FDA-approved. One genome-editing therapy treats an inherited blood disorder called beta-thalassemia, in which the body doesn’t produce enough red blood cells and thus isn’t able to deliver enough oxygen to muscles and organs. The single-dose treatment genetically modifies some of the patient’s own blood cells so that they function correctly. Researchers are hopeful that a similar genome-editing approach will also cure sickle cell disease, an excruciating genetic blood disorder affecting mainly people of African descent. A clinical trial for a CRISPR-based sickle cell treatment has shown “prolonged benefit” for participants, according to a report in STAT.

Team of surgeon doctors are performing a transplant surgery.
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A Brave New World of Animal-to-Human Transplants

The chronic shortage of human organs for transplants led a team of surgeons to take what some might view as a dramatic step. In 2022, in a medical first, a patient with severe heart disease received a brand new heart from a pig. The 240-pound, genetically modified animal had been raised for the purpose. The surgery, which took place at the University of Maryland Medical Center, was successful: the patient survived the procedure and was breathing on his own a couple of days afterward, with the heart pumping appropriately. However, the patient died two months after the surgery, likely due to a porcine virus that was transferred along with the heart; the patient’s weakened immune system couldn’t fight it off. Despite the unhappy outcome, many consider the experimental operation useful toward making xenotransplantation an option for people needing new organs.

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Interesting Facts writers have been seen in Popular Mechanics, Mental Floss, A+E Networks, and more. They’re fascinated by history, science, food, culture, and the world around them.

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Déjà vu (French for “already seen”) is not just the feeling that you’ve experienced something before — it’s also the sense that the feeling is eerie, uncanny, or even wrong. Scientists are still trying to figure out this mysterious but common glitch in the brain. Here are a few facts about déjà vu, from its early reputation as a paranormal phenomenon to its possible neurological origins.

Image of Émile Boirac.
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Déjà Vu Was First Identified in 1876

Émile Boirac, a French philosopher, described the sensation of déjà vu as “an illusion of memory” in the journal Revue Philosophique in 1876. “Upon seeing for the first time a monument, a landscape, a person, I suddenly and in spite of myself concluded: I have already seen what I see,” he wrote. “Impossible to say in what place or at what time; the recognition and the feeling of déjà vu was nonetheless very lively and very clear.” For years afterward, perhaps because Boirac also wrote about psychic phenomena and investigated psychic mediums, déjà vu was thought to be a kind of paranormal experience. Today, scientists have accepted the definition of déjà vu as “any subjectively inappropriate impression of familiarity of a present experience with an undefined past.”

Deja vu word in a dictionary.
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Déjà Vu Is Pretty Common

It isn’t easy to study such a fleeting and subjective phenomenon, but scientists estimate that about 60% of the healthy population have experienced déjà vu in their lives. Studies have suggested that younger people and those who are highly educated, well-traveled, and open-minded are more likely to experience it. The chance of having déjà vu also seems to decrease with an individual’s age, and it affects men and women equally. Stress and fatigue might trigger déjà vu, but it also occurs when people are relaxed and in social settings. In short, a lot more research is needed to understand it fully.

Close up of a MRI brain.
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Déjà Vu Might Be a Result of Mismatched Brain Signals

Déjà vu is linked with memory, and memory is associated with the brain’s temporal lobe. This connection has led some scientists to suggest that déjà vu is the result of a “mismatch” between what a person sees and hears in the present and memories stored in the temporal lobe. Usually, when people experience something new, that sensory information gets stored and recalled as short-term memories. During an episode of déjà vu, the new experience bypasses the short-term stage and brings up an older memory. But the mismatch means that the older memory doesn’t feel completely real or appropriate to the situation. Akira O’Connor, a lecturer in psychology and neuroscience at the University of St. Andrews, has suggested that the feeling of uncanniness may stem from decision-making areas in the brain’s frontal lobe “fact-checking” the mismatched signals it receives from the temporal lobe.

encephalography brain paper cutout on a purple background.
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Déjà Vu Is Linked to Epilepsy and Dementia

Another theory for the origin of déjà vu is based on evidence that people with temporal lobe epilepsy (TLE) or dementia often have déjà vu more frequently and for longer periods, and it doesn’t go away when the patients alter their gaze or surroundings. These experiences seem to suggest that déjà vu is a “random mental event” not tied to people’s perceptions of their environments. Research in the past two decades has focused on identifying the brain networks, in addition to the structures, that might underlie déjà vu; and whether there may be distinct types of déjà vu experienced by healthy people and those with TLE.

An antique copy of David Copperfield, by Charles Dickens.
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Déjà Vu Is a Plot Device in Countless Novels and Movies

Characters who have moments of déjà vu pop up in works as different as David Copperfield and The Matrix. In Charles Dickens’ novel, David Copperfield’s two instances of déjà vu suggest premonitions of his future; in the Wachowskis’ 1999 sci-fi thriller, Neo’s observation of a black cat walking by twice in exactly the same way (a “glitch in the matrix”) signals the possibility that worlds exist on multiple planes of perception. Other works in which déjà vu appears include Catch-22 by Joseph Heller, War and Peace by Leo Tolstoy, and the 1985 movie Desperately Seeking Susan.

Confused businessman staring at scribble a wall.
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The Opposite of Déjà Vu Is Jamais Vu

The sense that your surroundings are new and odd, despite realizing that you are familiar with them, is called jamais vu (“never seen”). It may be associated with different brain signals and it’s much less common than déjà vu, though it also occurs more often in people with TLE. Some researchers think there are more subtypes of déjà vu out there, such as déjà vécu (“already lived through”), in which the person has a strong but misplaced recollection of having lived through an experience that is new; and déjà visité (“already visited”), in which a person recognizes a specific landscape they’ve never been in.

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Interesting Facts writers have been seen in Popular Mechanics, Mental Floss, A+E Networks, and more. They’re fascinated by history, science, food, culture, and the world around them.

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Everyone knows about Cleveland’s Rock & Roll Hall of Fame, and even people who aren’t baseball fans likely remember the National Baseball Hall of Fame in Cooperstown, New York, from the scenes at the end of A League of Their Own. What you may not know, however, is that there are a lot of other halls of fame throughout the United States, honoring just about every sport, not to mention titans of industry, important inventions, iconic cars, and more. Here are six halls of fame you probably haven’t heard of.

Firefighter protection gear on the fire truck bumper.
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Hall of Flame Museum of Firefighting, Phoenix, Arizona

Perhaps the country’s most cleverly named hall of fame, Phoenix’s Hall of Flame Museum of Firefighting is a tribute to the heroes who fight fires and keep communities safe. Originally established in 1961 in Wisconsin, the museum houses firefighting equipment from as far back as 1725 across six impressive galleries, a theater, and a restoration shop. In addition to 130 fire trucks and vehicles, the galleries are also home to gear, tools, equipment, extinguishers, art, and artifacts from numerous countries. There are also hands-on exhibits and programs that teach kids about fire safety.

Perhaps most notably, the museum houses the National Firefighting Hall of Heroes. The space recognizes U.S. firefighters who have received awards for heroism, as well as those who have died in the line of duty. It also includes a tribute to the firefighters who lost their lives on 9/11, and exhibits detailing the work of women firefighters and volunteer firefighters.

International Tennis Hall of Fame in Newport, Rhode Island.
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International Tennis Hall of Fame, Newport, Rhode Island

Housed within the historic Newport Casino — a Shingle-style athletic complex on Newport’s Bellevue Avenue that dates back to 1880 — the International Tennis Hall of Fame overlooks 13 grass tennis courts. These aren’t just any courts, though — they hosted the earliest U.S. Open tournaments in the late 19th century and are now open for public play.

Inside, the Hall of Fame celebrates more than 250 tennis champions and some of the sport’s most iconic matches. You’ll also find a vast collection of modern and antique tennis artifacts ranging from art and apparel to equipment and trophies. The oldest bits of ephemera date back to the 12th century, but thoroughly modern exhibits celebrating the game include video highlights of more contemporary masters such as Andy Roddick, Andre Agassi, Pete Sampras, and Billie Jean King.

Heather DiPietrantonio and Smitha Uthaman look at a display depicting Inventor Steve Wozniak.
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National Inventors Hall of Fame, Alexandria, Virginia

Located within the campus of the United States Patent and Trademark Office, the National Inventors Hall of Fame highlights the work of more than 500 inventors, engineers, and scientists who hold patents to significant technologies. There are exhibits about well-known inventors such as Thomas Edison and Steve Jobs, of course, but the real magic is in discovering the less-famous folks behind the stuff we use every day — think ballpoint pens, wrinkle-free cotton, FM radios, and the Band-Aid.

Free to visit, the museum includes a digital portrait gallery where you can learn more about the inductees’ lives and accomplishments, a variety of displayed artifacts, and interactive kiosks that explain the processes of trademarks and patents. And in an effort to support the next generation of inventors, the facility also offers programming for youths — including a summer camp and partnerships for college students.

The Phillie Phanatic performs before a game.
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Mascot Hall of Fame, Whiting, Indiana

David Raymond is the original Phillie Phanatic — the fluffy green creature representing the Philadelphia Phillies Major League Baseball team. He’s also behind Whiting’s Mascot Hall of Fame, an interactive children’s museum on the shores of Lake Michigan. The facility offers 25,000 square feet of fun for kids of all ages. Shoot T-shirts out of a cannon, build your own mascot, or take the stage in a mascot audition — the space is a whimsical wonderland devoted to the mascots of North American sports.

While the museum is relatively new, having opened in 2018, the organization behind it has been honoring mascots since 2005. Each year, mascots are nominated across a series of categories from various sports and leagues. Only those that have existed for 10 years or more — and routinely give groundbreaking, crowd-pleasing, and inspiring performances — are eligible for induction.

Mural by artist Richard Haas outside the National Cowgirl Museum and Hall of Fame.
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National Cowgirl Museum and Hall of Fame, Fort Worth, Texas

Located in the Will Rogers Memorial Complex in Fort Worth’s Cultural District, alongside the Cattle Raisers Museum and the Fort Worth Museum of Science and History, the National Cowgirl Hall of Fame spans 33,000 square feet, all in tribute to the women of the American West and other female trailblazers. The Hall of Fame, which inducts new honorees each year, spotlights a diverse roster of rodeo champions, ranchers, entertainers, artists, writers, and pioneers — women such as Georgia O’Keefe, Sacagawea, Sandra Day O’Connor, Annie Oakley, and Dale Evans.

In addition to the Hall of Fame, visitors can peruse a rare photography collection, rodeo memorabilia, interactive exhibits on ranching and land stewardship, and a study on cowgirls in the media — think dime novels, honky tonk music, and Hollywood Westerns.

Close-up of the Chevy Corvette logo on a car.
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Corvette Hall of Fame, Bowling Green, Kentucky

Not many cars have their very own hall of fame and museum, but the Chevrolet Corvette is one of the most famous vehicles ever produced. Located just across the highway from the only GM factory that produces the sports cars, the National Corvette Museum features a racing simulator; a space highlighting Corvette models from each generation; a tribute to mid-century Americana, car culture, and the Corvette’s earliest days; and an exhibit on the infamous sinkhole that formed in the middle of the museum in 2014. Meanwhile, the Hall of Fame pays tribute to the most influential individuals in the history of the Corvette, from designers and engineers to hobbyists and race car drivers.

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Interesting Facts writers have been seen in Popular Mechanics, Mental Floss, A+E Networks, and more. They’re fascinated by history, science, food, culture, and the world around them.

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Even today, the highest position of executive power is held by a woman in only 15 countries (at the time of writing). Yet throughout history — dating back to the early civilization of Sumer — women have been making moves to speak up, fight back, and take action, continuing the millennia-long battle for gender equality in leadership.

From Hatshepsut in ancient Egypt and Queen of Sheba in southwestern Arabia to Catherine the Great of Russia and British royals such as Queen Elizabeth I and II and Queen Victoria, many female rulers have carved out their place in history — yet so many other greats have also made major strides but remain overlooked. Here are six of the strongest women who have ever ruled.

Portrait of Empress Elisabeth.
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Elizabeth of Russia

The daughter of Peter the Great, Elizabeth of Russia (born Yelizaveta Petrovna in 1709) remained relatively quiet during the reigns of her father (who ruled from 1682 to 1725), her mother Catherine (from 1725 to 1727), Peter II (1727 to 1730) and Anna (1730 to 1740). However, when Anna Leopoldnova stepped in as Russia’s regent for her son Ivan VI, Elizabeth staged a palace coup in 1741 and became empress.

Elizabeth immediately made bold moves, like ending the government cabinet council system and bringing back the Senate system her father had established. While many of her acts were reminiscent of her father’s reign, she also paved new ground, founding Russia’s first university in Moscow and an arts academy in St. Petersburg, as well as building the Winter Palace. But perhaps her greatest act was in May of 1744, when she demanded all the state prisons cease executions without a royal decree, requiring detailed reports of each prisoner on death row. While this didn’t formally abolish the death penalty, not a single person was executed during her 21-year reign from 1741 to 1761.  

Queen Tomyris by Andrea del Castagno.
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Queen Tomyris of Massagetae

Among the many paintings hanging in the Red Room of Hillsborough Castle in Northern Ireland is an oil canvas by Victor Wolfvoet from the 1600s titled The Head of Cyrus Brought to Queen Tomyris. In it, Persian king Cyrus the Great’s severed head is being forced to drink human blood, literally at the level of Tomyris’ feet. The queen’s triumphant moment symbolizes the victory of the Central Asia nomadic tribe of Massagetae over Persia across the river — a storied part of ancient history, which has cemented her lasting reputation as the “bad-ass Queen of the Steppes,” as described by Red Sonia comic book artist Mark Russell.

While many tales of Cyrus’ death have been told over the years, it’s generally believed he died around 529 BCE under the direction of Tomyris, who was merely trying to protect her dominion. After conquering Babylon, Cyrus turned his focus on Massagetae and how to best outsmart Tomyris. His first attempt: offering to marry her. But she saw right through that. Outraged, he started building ways to get across the river, but Tomyris is said to have responded, “Be content to rule in peace your own kingdom, and bear to see us reign over the countries that are ours to govern.”

Cyrus refused to give up and captured her son Spargapises in a bloody surprise attack to which she retorted: “Restore my son to me and get you from the land unharmed, triumphant over a third part of the host of the Massagetai. Refuse, and I swear by the sun, the sovereign lord of the Massagetai, bloodthirsty as you are, I will give you your fill of blood.” And it is with that motherly instinct mixed with pure sovereignty that she succeeded in making that promise come true.

Beach fales are pictured on June 2, 2017 in Saleapaga, Samoa.
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Queen Salamasina of Samoa

The male-dominated society of Samoa seemed like an unlikely place for a female ruler in the 15th century, but that was exactly what happened when Salamasina was given the “highest office in the western islands of Samoa.” But the traditions were so well-entrenched that several scholars have even referred to her as a “son” of Tuia‘ana Tamaalelagi.

Her reign came to be as a complex maneuvering of titles through bloodlines, some which were even strategized before her birth. Her adopted grandmother was set on making her tupu o’Samoa — the ruler of all Samoa. “One day she said, ‘This is it. This is the girl who can bring Samoa together,’” a historian explained in a Tagata Pasifika documentary, Women of Power in the Pacific.

While born into the role, Salamasina used it to ignite one of Samoa’s most peaceful periods — 60 years without warfare.

Boudica or Boadicea, Queen of the British Iceni tribe.
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Queen Boudica of Britain

Married to the king of Iceni (where modern East Angila is), Prasutagus, the Celtic queen Boudica is thought to have been born around 30 CE to a well-to-do family. When Romans took over southern England in 43 CE, Prasutagus was allowed to continue ruling, as long as he remained an ally. Upon his death 13 years later, both his kingdom and his family’s land were taken by the Romans since he didn’t have any male heirs. To make matters worse, Boudica was publicly flogged and her daughters were raped.

But Boudica was a trained warrior, unwilling to stand aside and watch this injustice and violence. “Nothing is safe from Roman pride and arrogance,” she said. “They will deface the sacred and will deflower our virgins. Win the battle or perish, that is what I, a woman, will do.” And around 60 CE, she led a revolution against the powerful Roman Empire.

Against the odds, she defeated the Roman Ninth Legion and destroyed Camulodunum, the center of Roman Britain, as well as London and Verulamium. But in the end, the Roman forces were just too strong. Boudica and her daughters are thought to have taken poison and killed themselves to avoid surrendering.

Ceremonial stone disk, The Disk of Enheduanna, daughter of Sargon of Akkad.
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Princess Enheduanna of Akkad

More than 4,000 years ago, Enheduanna, the daughter of the world’s first emperor, Sargon the Great, was given an essential task as the high priestess of the ancient city of Ur at the mouth of the Euphrates River: She had to find a way to to unite the various city-states of Sumer, which her father had conquered in the 24th and 23rd centuries BCE.

The priestess title meant that she was also the empire’s supreme religious leader, tasked with joining those who looked up to the Sumerian goddess of love and fertility, Inanna, with her dad’s deity, the goddess of war and sexuality Ishtar. And the Akkadian princess found the most innovative way to do so — with words.

As the first known poet, she had such a way with her verses and prayers that she’s seen as one of the most influential figures in religion, literature, and politics, making her “really powerful, and not just in a political domain: ritual supports politics and vice versa,” as St. John’s University art history professor Amy Gansell told National Geographic.

Saint Tamar of Georgia.
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“King” Tamar of Georgia

“I have long been fascinated by King Tamar,” Hillary Clinton said at a Town Hall with Georgian Women Leaders in 2010 when she was Secretary of State. “And some… may not know that King Tamar was a woman who led what is referred to as the Golden Age in Georgia.”

Indeed, the only daughter of the nation of Georgia’s King Giorgi was Tamara (also called Tamar), who the king made a co-ruler in 1178. When King Giorgi died in 1184, his daughter took over completely. While she was and is often referred to as “King Tamar,” she was a female ruler, and a prime example of standing up for women’s rights. Forced into an abusive relationship, she divorced her first husband, Prince George Boboglyubski of Kiev, and sent him into exile. When he recruited a rebel army to take her down, she triumphed once again.

After her 1213 death, she was made an Orthodox Church Saint for leading one of the greatest periods in the nation’s history.

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Interesting Facts writers have been seen in Popular Mechanics, Mental Floss, A+E Networks, and more. They’re fascinated by history, science, food, culture, and the world around them.

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Most of us spend around a third of our lives in bed, but how much time do you spend thinking about your bed itself? Folks didn’t always sleep alone (or with a partner) in private rooms on foam mattresses — if you were born tens of millennia earlier, you might even have slept in a hole.

What bed is so large that we still read verse about it today? Where did the term “California king” come from? These six facts about beds will give you something to think about when you’re drifting off to sleep.

Shell Mound People in their outside homes.
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The Earliest Beds May Have Been About Pest Prevention

Humans lived in Sibudu Cave in South Africa at least 77,000 years ago, and according to some archaeologists, early people made their beds there. Those passing through would gather plant matter from outside the cave, then pile it in shallow holes in the cave floor. The bedding included Cape laurel, an aromatic tree that’s a natural pest repellent. Laundry was pretty easy: People would periodically burn the bedding in the hole and start over, which researchers believe was a way of killing pests and cleaning up garbage.

The Great Bed Of Ware.
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We’re Still Reading About a Giant 16th-Century Novelty Bed

The Great Bed of Ware was constructed around 1590 in Ware, Hertfordshire, England, at the time about a day’s journey from London. Historians think it was made as a tourist attraction, and if that’s true, it was extremely successful — it was immortalized in popular verse, and people still visit it today at the London-based Victoria and Albert Museum.

The ornate canopy bed is a whopping 10 feet wide, 11 feet long, and nearly 9 feet high, and was often used as a literary device to imply either bigness or lewdness. Most famously, Shakespeare referenced the bed in Twelfth Night: “As many lies as will lie in thy sheet of paper, although the sheet were big enough for the bed of Ware.”

Legend has it that 26 couples (52 people!) spent one night in it together for a bet in 1689. That may be apocryphal, but countless people did sleep in it at one point or another. Some even carved their initials in the posts, many of which are still visible today.

Several people sharing beds in a pilgrimage.
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Bed-Sharing With Friends (and Strangers) Was Common Until Very Recently

Before bedrooms emerged (and for a while after), it was common to share not just rooms, but beds, too, and not even with people you knew particularly well. Even family beds were sometimes shared with the odd traveler. In wealthy households, servants would sleep at the foot of their boss’s bed. The 17th-century diarist Samuel Pepys often had sleepovers with his friends, sharing a bed and having conversations. Benjamin Franklin and John Adams even shared a bed once in a New Jersey inn; they could not agree on whether to keep the window in the small room open or closed. Large, communal beds at inns weren’t unheard of; travelers often slept with strangers (it’s even mentioned in Moby Dick). A French phrasebook for medieval travelers included phrases for admonishing bedmates. As far back as 5000 BCE, travelers shared large, stone beds in China and Mongolia, and brought their own bedding. People occasionally share beds with strangers today, too, although it’s not generally encouraged.

William Shakespeare and Anne Hathaway.
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Shakespeare Left His Wife His “Second-Best Bed”

Near the end of William Shakespeare’s last will and testament, he leaves a specific item to his wife, Anne Hathaway: “Item I gyve unto my wife my second best bed.”

It wasn’t meant to be insulting — beds were a major luxury item at the time, and the best bed was often a centerpiece item displayed in a common area and offered to guests. The second-best bed was probably the bed they actually slept in together. Scientific analysis of the will shows that the bed was a somewhat late addition to the document; it’s possible the Bard started bequeathing personal items after he knew he was dying.

Interior of modern bedroom.
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California Kings Came Before Regular Kings

California king mattresses are actually slightly narrower and longer than regular kings. But California kings were invented to be big, and at the time, they didn’t have a lot of competition.

Sometime between the 1920s and the 1940s, a Los Angeles mattress salesman wanted a glamorously large bed that he could market specifically to Angelenos with larger homes. He developed an 84-inch-long mattress and called it the California king.

After World War II, big beds started sweeping the nation, but other mattress manufacturers standardized the measurements a little bit so their king mattresses were the size of two twins pushed together. For a while, what we know now as just a “king” was called the “Eastern king.” At some point, the non-California bed dropped the qualifier and its longer counterpart did not.

Emptying and dismantling a waterbad mattress.
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Waterbeds Used To Be Medical Devices

When most people think of waterbeds, they think of the luxury item that rose to prominence in the 1970s. But the first modern waterbed came along in 1833, when Scottish inventor and doctor Neil Arnott invented the “hydrostatic bed for invalids,” designed to reduce recovery time, increase patient comfort, and reduce bedsores. By placing a soft mattress on top of a bath with waterproof rubber on top, he wrote, “[the patient] would repose on the face of the water, like a swan on its plumage, without sensible pressure anywhere.”

Waterbeds actually took off for a while in a medical setting, including in at least one Civil War army hospital. Meanwhile, the more recreational waterbed we’re used to now was invented in the late 1960s.

Sarah Anne Lloyd
Writer

Sarah Anne Lloyd is a freelance writer whose work covers a bit of everything, including politics, design, the environment, and yoga. Her work has appeared in Curbed, the Seattle Times, the Stranger, the Verge, and others.