The Nazis entered this war under the rather childish delusion that they were going to bomb everyone else, and nobody was going to bomb them. At Rotterdam, London, Warsaw, and half a hundred other places, they put their rather naive theory into operation. They sowed the wind, and now they are going to reap the whirlwind.

Statement of 1942, at the start of the bombing campaign against Germany, as quoted in "Sir Arthur Harris & The Lancaster Bomber" at The British Postal Museum and Archive