The Hitler and Mannerheim recording is a 1942 recording of a private conversation between German dictator Adolf Hitler, and Carl Gustaf Emil Mannerheim, Commander-in-Chief of the Finnish Defence Forces. It took place on a secret visit made to Finland by Hitler to honour Mannerheim's 75th birthday on 4 June 1942, during the Continuation War, a sub-theatre of World War II. Thor Damen, a sound engineer for the Finnish broadcaster Yleisradio (YLE) who had been assigned to record the official birthday proceedings, recorded the first eleven minutes of Hitler and Mannerheim's private conversation—without Hitler's knowledge. It is the only known recording of Hitler speaking in an unofficial tone.