What is something that most people don't know?

1. The Library of Babel: A digital library containing every possible 410-page book exists online.
2. Earth's Hum: The Earth emits a low-frequency hum that scientists have only recently discovered.
3. Infinite Fractions: Pi (π) is an irrational number with infinite decimal places, and it contains every finite number sequence.
4. The Baader-Meinhof Phenomenon: It's when you learn something new, and suddenly, you start noticing it everywhere.
5. Fingerprints of Koalas: Koalas have unique fingerprints like humans.
6. Octopuses Have Three Hearts: Two pump blood to the gills, and one pumps it to the rest of the body.
7. Bananas Are Berries: While strawberries aren't considered berries, bananas are.
8. The Eiffel Tower Shrinks in Cold Weather: It can contract up to 6 inches in winter.
9. The Smell of Rain: There's a word for it—petrichor.
10. Cows Have Regional Accents: Studies show cows moo with different regional dialects.