The answer is double jeopardy!
<span>The first striking change occurs with the appearance of new weapons. A machine gun was designed that used the recoil to operate the mechanism of the weapon in a continuous manner. The Parabellum-Pistole (Pistol Parabellum), is a semiautomatic pistol operated by recoil. There were three types of general-purpose pistols: revolvers, automatic pistols, and semiautomatic pistols. The rifle, became the most crucial infantry weapon, of the battlefields. The gases made their appearance sowing horror in the trenches, and the tank was undoubtedly one of the great novelties of the Great War.</span>
It was the battle of the bulge.