How many of you know what these are? Photo Credit: militarychallengecoins.com They are challenge coins! A challenge coin is a coin with an organization’s insignia and is carried by the members of that group. In the military, they are normally presented by commanders to recognize outstanding service or the special achievement of a member in the unit. The tradition goes back to WWI when the coin was being used to verify a person’s identity during meetings or membership to a specific ...