In the 1920s and 1930s, airpower theorists such as Giulio Douhet and Billy Mitchell claimed that air forces could win wars, obviating the need for land and sea combat. It was thought that "the bomber will always get through" and could not be resi…

London had nine million people—a fifth of the British population—living in an area of 750 square miles (1,940 square kilometres), which was difficult to defend because of its size. Based on experience with German strategic bombing during Wo…