Dragged forcefully by Japan into the Second World War, the United States of America in 1942 gradually increased its presence also in the Mediterranean basin. Here, until then, the balance of the conflict had always been in the balance between the Axis forces and the British and Commonwealth ones. Technological innovation and the arms race put in the field by the American war industry meant that quickly the fate of the conflict in the Mediterranean area changed radically in favor of the Allied forces. An unprecedented firepower was unleashed first on the cities of southern Italy and, in the course of 1943, on the whole national territory, leading to the fall of the fascist regime, then to the armistice and subsequently to the declaration of war by Italy to Germany itself. In a little less than three years, the Allied military force was able to conquer most of the Italian territory, reaching the capital, Rome, on June 4, 1944.