The strange side of being human

Your body is an absolute mystery—here are 10 reasons why

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The human body is full of hidden abilities, strange quirks, and biological wonders. Every function, from microscopic processes to large-scale systems, showcases the incredible complexity of our anatomy. Here are 10 extraordinary facts that prove just how fascinating we are.

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Your brain shrinks as you get older. The human brain starts losing volume in your late 20s, shrinking about 5% per decade after 40. Memory, coordination, and processing speed decline as neurons die and connections weaken, though mental exercises can help slow the process.

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Your body contains enough iron to make a small nail. The average human has about 4 grams of iron, most of it in the blood. This iron is crucial for transporting oxygen, and deficiencies can lead to anemia. The body loses iron daily, which is why dietary intake is essential.

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Your stomach acid can dissolve metal. Gastric acid has a pH between 1 and 2, strong enough to break down food, kill harmful microbes, and even dissolve razor blades in lab conditions. The stomach lining regenerates quickly to prevent self-digestion.

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Your eyes have a spot where you see nothing. The optic nerve creates a blind spot where it exits the retina, meaning there's a part of your vision with no data. The brain fills in the gap using surrounding images, making the flaw almost unnoticeable.

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Humans are bioluminescent. Our bodies emit small amounts of light due to biochemical reactions, but it’s 1,000 times weaker than the human eye can detect. Specialized cameras have captured this glow, with faces and hands shining the brightest.

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The strongest muscle isn’t what you think. The masseter (jaw muscle) exerts the most pressure, capable of generating up to 200 pounds of force. Meanwhile, the heart beats 100,000 times daily, making it the hardest-working muscle.

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Your nerves transmit signals at up to 268 mph. The fastest nerve fibers, found in the spinal cord, send impulses almost as fast as a Formula 1 car. This rapid communication allows for quick reflexes and split-second reactions.

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Sweat itself doesn’t smell. The odor comes from bacteria breaking down proteins in sweat, particularly in areas with apocrine glands, like the armpits. Diet, stress, and hygiene all play a role in body odor intensity.

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Ounce for ounce, bone is stronger than steel. The femur, in particular, has a compressive strength of about 18,000 psi. Bones are also lightweight and flexible, making them ideal for movement and impact absorption.

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Your brain can store around 2.5 petabytes of data. That’s equivalent to about three million hours of TV shows. The brain’s vast storage relies on neural connections and electrical signals, with synapses constantly forming and breaking as you learn new information.

Secrets in plain view

The untold stories behind 15 of the world’s most famous artworks

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Art is often more than just visually stunning; it can carry deep, hidden meanings and symbols that offer a richer experience when understood. From elements that tell part of the artwork’s story to deliberate messages and strange secrets, here are 15 famous artworks with hidden layers you might not have noticed before.

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Though the Mona Lisa is perhaps the most famous painting in the world, the identity of the woman in the portrait has long been a subject of debate. Most scholars believe she is Lisa Gherardini, a Florentine woman married to a wealthy merchant, Francesco del Giocondo. However, numerous alternative ideas have emerged, including theories that the subject is an idealized figure or even a concealed self-portrait of Da Vinci.

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Rodin’s famous sculpture, The Thinker, was originally conceived as part of a larger work but became iconic in its own right. Despite its fame, many curious facts about the sculpture are often overlooked. For example, its original name was actually The Poet, which supports the theory that the statue was meant to depict Dante.

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Botticelli’s The Birth of Venus blends classical mythology with Renaissance ideals of beauty. Venus, standing on a shell, symbolizes divine beauty and spiritual rebirth. Curiously, some believe it was modeled after the long-lost Venus Anadyomene, a painting by the ancient Greek artist Apelles, known only through Roman author Pliny the Elder’s description.

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Munch’s The Scream captures a moment of extreme emotional distress. The swirling sky, vivid in color, reflects the inner turmoil of the subject. While Munch claimed the inspiration came from a panic attack he experienced while walking, some argue that the red skies may have been inspired by the eruption of Krakatoa in 1883, which caused vivid sunsets around the world.

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In Raphael’s The School of Athens, ancient philosophers are depicted in conversation, but the placement of the figures is deliberate. Plato and Aristotle are centrally placed, with Plato pointing upwards, symbolizing his belief in ideal forms, while Aristotle’s gesture points horizontally, emphasizing his empirical approach.

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The Statue of Liberty is not just a symbol of freedom; its design includes several symbolic elements. The broken chain at her feet represents the abolition of slavery, while the torch symbolizes enlightenment. But most curiously, Lady Liberty's face is said to have been modeled after the artist Frederic-Auguste Bartholdi's mother.

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Da Vinci’s Last Supper holds numerous symbols, most notably the geometric composition. The table itself forms a triangle, symbolizing the Holy Trinity, while Christ’s position in the center divides the composition into a perfect balance of divine and human. Even the placement of Judas, isolated from the others on the opposite side of Christ, visually hints at his betrayal.

Credit: Ján Jakub Naništa

Grant Wood’s iconic American Gothic has often been interpreted as a commentary on rural American values, but there are more layers to the painting. In fact, it was inspired by a real house built in the style of "Carpenter Gothic," which Wood found rather pretentious for such a humble home. The characters, however, aren’t the real inhabitants of the house but Wood’s dentist and his sister.

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The Venus de Milo represents idealized beauty in ancient Greek sculpture, but its missing arms add to its mystery. The lost limbs have sparked theories about its original pose, enhancing the statue's allure. Interestingly, some suggest the figure may not depict Aphrodite/Venus at all, but Amphitrite, the sea goddess worshiped on the island of Milos.

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A master of visual storytelling, Rembrandt was well known for including hidden messages and symbolism. In his masterpiece The Night Watch, some believe the artist makes a subtle cameo. In the middle of the painting, behind a man in green and a guard with a metal helm, you can spot a faint figure, widely thought to be Rembrandt himself.

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Leonardo’s Vitruvian Man is not just a study of human anatomy; it symbolizes the Renaissance belief in the harmony between art and science. But beyond the perfect proportions, keen observers have noted that the man depicted appears to suffer from an inguinal hernia—an ailment that could have been fatal at the time. Given that artists often used cadavers as models, it's likely that Leonardo based the figure on a real, deceased individual.

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Klimt’s The Kiss is renowned for its use of gold leaf, evoking the sacred beauty of religious art found in churches. Some art historians even speculate that the lovers in the painting are not just symbolic figures, but a representation of Klimt himself and his long-time partner, fashion designer Emilie Flöge.

Credit: Pierre Herman

Delacroix’s Liberty Leading the People uses the allegorical figure of Liberty to symbolize the spirit of revolution during France's July Revolution of 1830. However, the woman in the painting has a name—_Marianne_—a powerful symbol of the French Republic ever since the first French Revolution of 1789.

Credit: Jean Carlo Emer

Van Gogh's Self-Portrait with Bandaged Ear captures a deeply personal moment following the infamous incident in which he—allegedly—severed his own ear. However, some art historians now believe that the wound was in fact the product of an altercation with friend and fellow artist Paul Gauguin. A deft fencer, Gauguin might have acted in self-defense during a violent bout of psychosis of his friend.

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Michelangelo’s David symbolizes strength and humanism, embodying both intellectual and physical power. While its proportions follow classical ideals, David’s unusually large head and oversized right hand stand out. Additionally, his heart-shaped pupils are a curious detail, possibly symbolizing his love for Florence or a playful nod to the letter "D," often depicted as a heart in Renaissance art.