U-boats

In little more than 80 years the submarine has evolved from a quaint mechanical tube into a weapon capable of destroying civilisation. Although submarines existed from the time of the Revolutionary War when Bushnell invented the Turtle, there was one force which transformed this curious invention into a weapon of destruction which in the modern age carries nuclear warheads capable of wiping out any city in the world within minutes. The force which brought the submarine to the attention of the world's militarists was the German Navy in Wold Wars I and II.