A letter shows that, despite his denials, Albert Speer knew about the Final Solution:

A newly discovered letter by Adolf Hitler’s architect and armaments minister Albert Speer offers proof that he knew about the plans to exterminate the Jews, despite his repeated claims to the contrary.
Writing in 1971 to Hélène Jeanty, the widow of a Belgian resistance leader, Speer admitted that he had been at a conference where Heinrich Himmler, the head of the SS and Gestapo, had unveiled plans to exterminate the Jews in what is known as the Posen speech. Speer’s insistence that he had left before the end of the meeting, and had therefore known nothing about the Holocaust, probably spared him from execution after the Nuremberg trials at the end of the second world war.