🌍Only 3 countries don't use metric: USA, Liberia, and Myanmar
📏A 'foot' was originally based on the length of a king's foot
🚀NASA lost a $125M Mars orbiter due to metric/imperial unit confusion
⚖️The kilogram was redefined in 2019 using Planck's constant, not a physical object
🌡️-40° is the same in both Celsius and Fahrenheit
🏃A marathon is 26.2 miles or 42.195 km - an oddly precise distance
🌊A nautical mile is based on Earth's circumference: 1 minute of latitude
💎Carats for gems (200mg) and karats for gold (purity) are different units