Here’s a weighty little gem from history: in ancient Egypt, the unit of weight was the “deben,” and it wasn’t just used for measuring goods—it was also a form of currency. People would weigh out copper or gold in debens to pay for everything from bread to beer. Imagine going shopping and pulling out a chunk of metal instead of a credit card!

And here’s a twist: the metric system—which gave us the kilogram—was born during the French Revolution as part of a push to simplify and unify chaotic local measurements. Ironically, the man who helped define mass scientifically, Antoine Lavoisier, was executed during that same revolution.