 Also helping Bruno Ganz (qv) in preparing for the role was the  unique, only known recording of Adolf Hitler (qv) when he held a  private conversation with Field Marshal Gustaf Mannerheim (qv) of  Finland (WWII ally of Germany against Soviet). Hitler unexpectedly  showed up to congratulate Mannerheim on his 75th birthday on June 4,  1942. Finnish intelligence agents secretly made the recording in a  train wagon (Hitler did not allow recordings nor photographs to be  taken in private). Some 11 minutes of the recording feature relaxed,  normal