The recording of Hitler's voice was hidden in 1942. It contains the first 11 minutes of a monologue as he had a private conversation with the Finnish general Carl Gustaf Emil Mannerheim. Hitler hardly raised his voice. He spoke only of several minutes for the unexpected and overwhelming number of tanks and military aircraft of the Soviet Union, which Germany tried desperately to destroy. Hitler is known to have great monologues often when he was with the people of the inner circle of.

During the visit, the engineer of the Finnish company YLE emissions, Thor Ladies, He managed to record the first 11 minutes of private conversation Hitler and Mannerheim. This had to be done secretly, as Hitler did not allow others to record without being aware.

After 11 minutes of private conversation Hitler and Mannerheim, bodyguards SS Hitler saw the cables hidden microphones and realized that the Finnish engineer records the conversation. They asked him to immediately stop recording and complied. Then they asked the immediate destruction of the film, but YLE kept the film after he promised to keep it sealed. The film in 1957 returned to YLE and went on display a few years later. This is the only known recording of Hitler informal.