37. Indian Powerplus
Source: US Army & The Library of Congress
Once World War I kicked off, Indian motorcycles dedicated almost all of their production to the war effort. The result saw 50,000 Indian Powerplus Big Twins (faster and more nimble than their Harley counterparts due to a re-designed rear suspension). Fast on their own, the military could also opt to install a sidecar outfitted with a machine gun to strike terror on the battlefield. However, after the war, Indian had trouble re-integrating into domestic production. Ultimately, it would become their downfall, but not before giving us a few incredible war time photographs.