10 Facts That Will Make You Question Everything You Learned in School

10 Mind-Blowing Facts You Weren’t Taught in School The world is full of strange, surprising, and sometimes downright unbelievable truths—many of which never make it into our school textbooks. Whether they’re hidden by history, buried by science, or just too weird to fit into a classroom curriculum, these facts will challenge what you thought you knew about reality. Get ready to have your mind blown.

1. Octopuses Have Three Hearts and Blue Blood Let’s start under the sea. Octopuses, those strange and brilliant creatures of the deep, don’t just have eight arms—they have three hearts. Two pump blood to the gills, and the third sends it to the rest of the body. Even weirder? Their blood is blue, not red, because it contains copper-based hemocyanin instead of iron-based hemoglobin. This helps them survive in cold, low-oxygen environments. So, next time someone says you have a big heart, remember the octopus has three.

2. Bananas Are Technically Berries, But Strawberries Aren’t Get ready to question everything you know about fruit. According to botanical definitions, a berry is a fruit produced from the ovary of a single flower with seeds embedded inside the flesh. By that logic, bananas, kiwis, and even eggplants are berries. Strawberries, on the other hand, grow from a flower with multiple ovaries and have their seeds on the outside—so they’re not true berries. Science can be a real fruit salad.

3. There Are More Stars in the Universe Than Grains of Sand on Earth Ever looked up at the night sky and felt small? Multiply that feeling by infinity. Astronomers estimate there are around 100 billion galaxies in the observable universe, each containing hundreds of billions of stars. That’s more than all the grains of sand on all the beaches and deserts of Earth combined. You’re not just a speck in the universe—you’re a speck on a speck.

4. Your Body Glows in the Dark (But You Can’t See It)Humans are literally glowing with light—bioluminescence—but it’s a very faint glow, about 1,000 times weaker than the human eye can detect. Japanese researchers captured this glow using ultra-sensitive cameras, and it turns out we emit the most light from our cheeks, foreheads, and necks. So yes, you shine—just not brightly enough for anyone to notice.

5. A Day on Venus Is Longer Than Its Year Time is weird on Venus. It takes the planet about 243 Earth days to rotate once on its axis—but only 225 Earth days to complete one orbit around the Sun. That means a day (sunrise to sunrise) on Venus is actually longer than a year. And since Venus rotates backward (retrograde), the Sun rises in the west and sets in the east. Mind officially twisted.

6. You Share 60% of Your DNA With Bananas You’re more like a banana than you think. About 60% of human DNA is identical to that of a banana. That doesn’t mean you’re going to start photosynthesizing anytime soon, but it does show how deeply connected all life is. On a cellular level, the lines between species can be surprisingly blurry.

7. Some Turtles Can Breathe Through Their Butts Yes, you read that right. Some turtles, like the Australian Fitzroy River turtle, can perform a type of respiration called cloacal respiration—essentially absorbing oxygen through their rear ends. It’s not their only method of breathing, but it comes in handy when they’re underwater for long periods. Nature is wild and full of surprises.

8. The Eiffel Tower Grows Taller in Summer Metal expands when it gets hot, and the Eiffel Tower is no exception. In the heat of summer, the iron structure can grow by about 6 inches (15 centimeters). At night or in cooler seasons, it contracts again. So yes, the Eiffel Tower is technically alive… or at least, stretching.

9. The Human Brain Has More Connections Than the Milky Way Has Stars Your brain is astonishing. It contains roughly 86 billion neurons, and each can connect to thousands of others, resulting in trillions of connections—called synapses. Some estimates suggest that the number of connections in a human brain may exceed the number of stars in the Milky Way galaxy. That makes your brain more complex than the galaxy we live in. Not bad for something that fits inside your skull.

10. Time Moves Slower the Higher You Go Einstein’s theory of general relativity says that time is affected by gravity. The stronger the gravitational field (closer to Earth’s surface), the slower time moves. This has been proven by placing synchronized atomic clocks at different altitudes—clocks on a mountain tick faster than those at sea level. Technically, astronauts age slightly faster than the rest of us. So if you want to live longer, stay grounded.

Final Thought: Reality Is Stranger Than Fiction If these facts prove anything, it’s that the universe is far weirder—and more wonderful—than we were led to believe in school. From glowing humans to breathing turtles and time-warping mountains, the real world is full of bizarre truths hiding in plain sight. The more you learn, the more you realize how little you actually know.

So stay curious, question everything, and never stop learning. Because the next mind-blowing fact could change the way you see the world forever.