In 1939, the world went to war. Yet most countries used obsolete weaponry. Even Germany's largest armies still relied on horse-drawn transport equipment. In order to gain supremacy it was necessary for an army of designers, inventors and manufacturers to develop and implement the manufacture of more and more sophisticated killing machines. Weapons of World War II charts the development of each weapon system, from the outbreak of war through to its 1945 climax. World War II saw 55,000-ton battleships become obsolete in the space of five years. It saw the emergence of the aircraft carrier become the most potent weapons platform the world had ever seen. It saw the introduction of tank warfare from lightweight underpowered vehicles of 1939 to the prototype of a 65-ton monster The Maus. This period also saw the emergence of rocketry with designs for rockets, which could be fired from Germany to reach New York.