Albert Speer's testimony in the series is now considered highly unreliable. Speer considerably downplayed his involvement in Nazi atrocities. After his death a letter he wrote in December 1971 proved he had full knowledge of the Holocaust throughout its course, despite his repeated public denials.
Albert Speer was interviewed by Martin Smith, who strongly disliked the entire experience. Smith was disgusted that Speer seemed unashamed of his role in the Nazi regime, but he had to be polite in order for the interview to proceed. He still feels uncomfortable about the experience.
It was unknown when the series was made that the fascist Spanish dictator Francisco Franco had offered to join the Axis on 19 June 1940, but had demanded Cameroon for Spain, which was unacceptable to Hitler. Admiral Erich Raeder had insisted Germany needed Cameroon for Plan Z.
Although the invasion of the Soviet Union is often portrayed as a mistake and a turning point in the war, in reality Adolf Hitler could not continue the war against the British Empire without vastly increased reserves of oil and grain. He was forced to turn east after the failure to defeat the UK in 1940-41, in order to seize the natural resources.
Without the invasion of the Soviet Union on 22 June 1941, Germany would have run out of oil by August and would then have been unable to continue the war against the British Empire.