World War I was at first fought with cavalry units with swords and small arms weapons. However, this small arms fire did not last throughout the war. Although these weapons may have taken a while to become present during the war, they were huge assets to any side that they had fought on. Tanks, mustard gas, and airplanes not only changed the way wars were fought, but they changed many more wars to come. Tanks were first introduced in World War I on September 15, 1916, the tanks were used to combat trench warfare the tracks known as caterpillar tracks gave the tanks a good grip in the mud and allowed them to travel over rough terrain that other vehicles could not. Their heavy armor made them slow but protected the crew from small arms fire
