We spend it, we save it, we send it. But how much do we really know about money?

In a bid to understand the thing that makes the world go round, we thought we’d explore some fun facts about money. Some of them are rather astonishing (who knew that money dates back more than 5,000 years?) and some are a little bleak (global debt, we’re looking at you). Nevertheless, these facts about money have confirmed that money is indeed a fascinating thing.

Ready to learn a thing or two? Here are 10 fun facts about money.

1. Money dates way back

Money has been a part of human history for at least 5,000 years. Before then, a system of bartering was likely used. The world’s oldest coin dates back to 600 BCE in China, which then moved to paper money around 700 CE. But for parts of Europe, it took until the 16th Century to switch from metal coins to paper money.

2. Paper money enabled international trade

Once the shift to paper money had occurred, international trade began to increase. Currency value began to depend on the strength of a particular country’s government or monarchy and before long, currency wars had started.

3. Two new forms of currency launched in the 21st Century

Mobile payment technology and virtual currency are two new forms of currency that launched in the 21st Century. Mobile payments are used to pay for products and services through a smartphone or tablet, while virtual currency is a digital representation of value that functions as a medium of exchange. It is not controlled or regulated by a central bank.

4. It costs more than a cent to make a cent

In the US, it costs roughly 2 cents to make a 1-cent coin. For a nickel (5 cents), it’s 7.5 cents. These extra costs quickly add up. In 2018 (when the most recent figures were available), it’s estimated that cent production cost the US taxpayer an extra $85.5 million and nickel production an extra $33.5 million.