Challenge Coins originated in ancient times and were given to soldiers as a reward for their service. The modern tradition of challenge coins gained popularity during the first World War when custom-made medallions were commissioned for military units. The practice of "challenging" with a coin emerged during World War II, where soldiers would carry their unit's coin at all times and use it to initiate a drinking game. Today challenge coins are also used by various groups such as Civil Air Patrol to recognize achievements, commemorate special events, and promote camaraderie. And just like patches, they have become collectible due to their unique designs and historical significance.