Human beings are obsessed with money. In the modern world, it dictates our work, our play and our interactions with friends and family members. Our very survival depends on it. While talking about money can cause worry and stress (arguments about it are the top predictor of divorce, according to a university study), it can also give us a window into other cultures. As such a vital part of life, learning about foreign currency can teach us about the people in the country where that money is used. Here are 10 fun, interesting — and sometimes gross — facts about foreign currency.
1. The most valuable foreign currency, as of summer 2018 (fluctuation in markets can change this ranking), is the Kuwaiti Dinar. One dinar is worth approximately $3.30. The British Pound is the fifth strongest currency, and the United States Dollar is the 10th strongest.
2. On the flip side, the least valuable foreign currency as of summer 2018 is the Iranian Rial. The current exchange rate is approximately 43,000 rial to $1 USD, or 1 rial to $0.000023 USD.
3. The Guinness World Record for the individual featured on the most currencies is held by Queen Elizabeth II, who is pictured on the money of at least 35 countries (all part of the British Commonwealth).
4. There’s probably cocaine on your cash. Nearly 90 percent of U.S. and Canadian bills, 99.9 percent of U.K. pound notes and 94 percent of Spanish Euros contain traces of cocaine. Interestingly, Chinese and Japanese bills had much lower rates of cocaine contamination.
5. Cocaine’s not the only thing tainting money: it also can play host to bacteria and disease. Research has found that both paper currency and coins can spread Staph infection–causing bacteria, E. coli, Salmonella, the flu and more.
6. Making pennies costs more than they’re worth, literally. In 2017, it cost the U.S. Mint about 1.8 cents per penny for manufacturing and shipping. All told, it added up to $69 million lost compared to their face value.
7. The British Pound Sterling is the oldest currency still in use. The silver coins date back to around 775 C.E., when they were widely used throughout the Anglo-Saxon period.
8. Much of the world’s money isn’t exactly vegan-friendly. Polymer bills, introduced by countries ranging from Canada to Paraguay to Vietnam, contain small amounts of tallow — a substance made from animal fat. At least 24 countries use currency made with tallow.
9. Pop culture lovers may have a new favorite travel destination. The tiny Pacific island of Niue, which uses the New Zealand Dollar as its currency, annually releases commemorative coins featuring Disney princesses, Star Wars characters, Pokémon and other fan favorites.
10. It’s truly a digital world. Economists estimate that only 8 percent of the world’s currency is actually physical money. The vast majority of it exists in online bank accounts.