Hitler and Mannerheim recording

[8] At Immola Airfield, Hitler was greeted and accompanied by President Risto Ryti and Finnish officials to Mannerheim's personal train, where a birthday meal and negotiations took place.

[7][9] In this wagon, a large and visible microphone had been set up by Thor Damen, a sound engineer for the Finnish broadcaster Yleisradio (YLE), who had been assigned to record Hitler's official speech and birthday message to Mannerheim.

[10] He extensively discussed the Winter War, Molotov's demands over Europe, and concerns over the Soviet occupation of Bessarabia and Northern Bukovina, which put Germany at risk of losing its petroleum supplies controlled by Romania.

[10] He discussed the failure of Operation Barbarossa, Italian defeats in North Africa, the invasions of Yugoslavia and Greece, his surprise at the Soviet Union's ability to produce thousands of tanks, and his strategic concerns about Romanian petroleum wells.

[10] Aside from this broad summary of the war in the East, Hitler did not reveal any of his future military plans, specifically an upcoming German offensive, of which the Finns were informed only the day before it occurred – much to Mannerheim's exasperation.

[12] Specialists from postwar Germany's Federal Criminal Police Office later examined the tape, and Head of Frequencies Stefan Gfroerer declared that it is "very obvious to us that this is Hitler's voice.