On Sept. 28, 1918 on a battlefield in France, a wounded German soldier shuffled right into the line of fire of a British soldier named Henry Tandey. Tandey raised his rifle. But when he understood the German was hurt and could not fight back, Tandey lowered his weapon. The German soldier realized he was in the crosshairs. He nodded thanks to his potential slayer—then scurried away. The German soldier was Adolf Hitler, then 29 years old.