Whether you're in the military yourself, have a relative who is, or you're just interested in collecting military paraphernalia, the use of challenge coins is perhaps one of the most interesting customs - and the coins themselves, in an amazing array of variations for different units and purposes, are great keepsakes.
While used in all branches of the service, no one seems to love challenge coins as much as the U.S. Marine Corps. There are probably more variations of Marine Corps challenge coins than any other branch has, and they are still in active use for "challenges" by Marines today.
But where do challenge coins come from?
The truth is no one knows the exact origin of challenge coins, but there are several plausible legends. The earliest of them starts in World War I, "the Great War".