On June 4, 1942, a private conversation between Adolf Hitler and Carl Gustaf Emil Mannerheim was secretly recorded when Hitler visited Mannerheim to congratulate him on his 75th birthday. This recording is one of the very few where Hitler can be heard not raising his voice and is the only known recording of him speaking in an unofficial tone.
Thor Damon, an engineer for the Finnish broadcasting company Yleisradio Oy (or Yle) was assigned to record Hitler's official speech and birthday congratulations to Mannerheim, but after greetings and speeches were done, Hitler and Mannerheim retired to the latter's private wagon. Damon had secretly set up a large microphone and recorded the first 11 minutes of Hitler and Mannherheim's conversation without their knowledge. During the conversation, Hitler discusses the failure of the Axis invasion of the Soviet Union, the Soviets' ability to produce numerous tanks, Italy's defeats in Africa and Southeast Europe and other concerns in the German war effort.
After 11 minutes, Hitler's SS guards realized what Damon was doing and gestured him to immediately stop recording. It is not known if Hitler or Mannerheim were made aware of their conversation being recorded. The SS guards demanded that the tape be destroyed but Yle was allowed to keep it under the condition that it be kept in a sealed container and never be opened again. However, in 1957, it was made publicly available and can still be listened to to this day.
The authenticity of the tape has been questioned by some. Rochus Misch a former body guard of Hitler, stated after listening to the tape that it sounded like someone trying to mimic Hitler. While Dr. Stefan Gfroerer of the German Federal Criminal Police Office has stated that it was very obvious that it is Hitler speaking. Whether it is authentic or not, it is an interesting listen, nonetheless. Something I think any World War II buff should hear. [center][youtube=https://www.youtube.com/watch?v=ClR9tcpKZec][/center]