This odd German war machine featured twin engines, a reversible gearbox, and the ability to drive in either direction. But its long, box-like hull hung so far over the tracks that it easily dug itself ...

Image Credit: Survival World ...

In just a few decades, the U.S. Army would see itself go from a single-shot, blackpowder design in the form of the Trapdoor Springfield to a modern, semi-automatic fighting rifle in the M1 Garand.