After Stalingrad, Hitler desperately needed an encouraging novelty. Wernher von Braun, Germany’s leading rocketeer in the second world war, expertly and persuasively briefed him on the latest secret weapon, a powerful ballistic missile, with a film to demonstrate its capabilities. Hitler was enchanted. He said: ‘Gentlemen, I thank you. If we had had these rockets in 1939, we should never have had this war.