Four weeks after D-Day, having fought fiercely for 28 consecutive days, American troops were still within eyeshot of the Normandy coast. They were already short of artillery rounds, but Gen. Omar Bradley didn’t care. The commander of U.S. ground forces was determined to send the enemy a message. And so, to mark U.S. independence on July 4, 1944, Bradley ordered every artillery piece in the American sector to fire one round at noon — in the enemy’s direction. The 1,600-gun salute sent German defenders ducking for cover along the front.