WWI US World War I Military Commemorative Challenge Coin - 100 Years - Nickel Silver 1917-1918 Centennial World War I Challenge Coin - No Certificate of Authenticity is available This exclusive coin continues the rich heritage of challenge coins found throughout the storied past of the U.S. military - stories that date back to The Great War and beyond. The act of presenting coins for valor can be traced to the early days in Ancient Rome. The obverse side of this custom die struck coin proudly displays the WW1  100 Years design with the silhouette of the U.S. Doughboy flanked by barbed wire that was prevalent during trench warfare. The reverse side serves to honor each soldier with the insignia worn on uniforms upon their return from The Great War. Each 1-3/4 die struck nickel-silver finish coin has a hand - decorated enamel color inlay to enhance the commemorative design.