In today’s world, people can make purchases with a simple swipe of a credit card or the click of a mouse button. But for the vast majority of human history, people had to carry around coins, or other material goods to trade in barter. Not only are coins rather cumbersome, but they also do not include the travel perks that many modern credit cards offer.

However, from the massive 12-foot coins of Micronesia to modern quarters, coins continue to fascinate collectors and history buffs alike. Recently, though, archaeologists uncovered a hoard of bronze coins at the bottom of the Mediterranean Sea, which could unlock several mysteries about the Roman Empire.