Hi I'm Adrienne, welcome to our lovely salon. This is Mental_Floss video and did you know that some currency is cleaner than others? In 2013 Turkish researchers coated 7 different currencies in all sorts of bacteria to test how long they survived. The Croatian Kuna won, with bacteria only surviving three hours, and because it's made of plastic, the Romanian Leu was still infectious the next day. And that's the first of many facts about money and currency that I'm gonna share with you today.

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Let's start with some history of currency. Originally people bartered and traded to get the goods they needed. Animals are actually one of the oldest forms of currency. Experts believe that people started trading cattle and livestock around 9,000 BCE. Shells were another early currency, there's evidence that they were used for money at various points in time all around the world, including Asia, Australia, and North America. In Africa, there were places where shells were still currency as late as 1900 CE.

China is responsible for what we recognize as money today. For instance, they started making coins during the stone age, and many experts consider China's decorated leather money from around 118 BCE to be the earliest form of the bank note. Then, during the Tang dynasty, which was around 618-907 CE, paper became a part of Chinese currency. Western countries didn't begin to use paper money until around the 17th century.

On the island of Yap which is now part of Micronesia, they used rai stones as money until the early 20th century. Rai stones were carved our of limestones and they could be as large as 12 feet in diameter.

Legend has it that the British got the term "quid" meaning one pound from the expression "quid pro quo," a Latin phrase referring to an equal exchange.

Since the 12th century, the UK has had about one Trial of the Pyx each year. This is a ceremony to determine that coins have been minted using the proper standards.

In Australia, a man named Francis Greenway appeared on the $10 note from 1966 to 1993, which is interesting because he was convicted of forgery in the 19th century. It's believed he's the only forger to ever appear on a country's currency.

After World War I, Germany experienced such bad inflation that many people used bank notes for things like wallpaper, because they were worth so little. Another country that's dealt with inflation is Zimbabwe. In fact, in 2009, the country's officials had to create a 100 trillion dollar note in order to keep up with inflation. It was worth around 40 US cents. And Hungary went through serious inflation in the 1940s. At one point the made a 40 quintillion pengo note, which was worth about 20 cents in America at the time.

The original ATMs required vouchers imprinted with radioactive ink, or else the machines wouldn't be able to read and process them. Speaking of ATMs, there's one in Antarctica. Wells Fargo installed one at the science hub McMurdo station in 1998.

For centuries, Italian banks have accepted cheese in exchange for good rates on loans. Nowadays a cheese maker can get a 3-5% interest rate on a loan if they leave the cheese at the bank to mature.

Canadian bank notes have a tactile feature for people who are visually impaired. The five dollar note has six dots, the ten dollar note has 12, the 20 dollar note has 18, and so on.

Each year the US government destroys a lot of money. That's why you still get crisp dollars from the bank, and it's rare to find a bill older than the 1990's. In 2010, the government got rid of 2.6 billion one dollar bills. The average time a US bill is in circulation before being destroyed is fairly short, about five years, and this depends on what it's worth. For instance, a 1 dollar bill lasts about 3.7 years, a 20 dollar bill lasts about 5.1 years, and a 50 dollar bill lasts the longest: 12.6 years. Because who uses 50 dollar bills?

People rarely use physical money anymore. About 95% of transactions that take place in the US today don't involve an exchange of physical dollars or coins. And that might be a good thing, according to a study conducted at the University of Massachusetts in Dartmouth in 2009, 90% of dollar bills contained traces of cocaine.

Queen Elizabeth the 2nd has appeared on currencies from 33 separate countries. The first time was in 1935 when she was featured on the 20 dollar note in Canada. She was nine years old. Talk about overachiever.

According to the European Commission, the parallel lines in the Euro symbol represent the stability of the currency. Really? One unstable part of the currency ended up being the 500 euro note. In 2010, they were removed from many businesses after experts determined that 90% of the notes in circulation were connected to crime, tax evasion, or terrorism. But only 120,000 1 euro coins are taken out of circulation annually for being counterfeit. Compare that with the 2 million one pound coins the UK removes. It could be because the pound is more attractive to forgers.

Finally, I return to the salon to tell you that when JK Rowling was asked about the Wizarding World's currency, she claimed that "[A galleon is worth] about five pounds, though the exchange rate varies."

Thanks for watching Mental_Floss video, which is made with the help of all of these nice people. Again, I'm Adrienne, and I also host CrashCourse Economics which you can check out here, and let me know in the comments section what you would buy in Diagon Alley with a galleon? Bye.

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