How an SS officer tried to get the Pope to condemn the Holocaust
Until this weekend, I had never heard of Kurt Gerstein.
In the Second World War, he was a SS officer and member of the Institute for Hygiene of the Waffen-SS who witnessed mass murders in the Nazi extermination camps at Belzec and Treblinka. He gave information to the Swedish diplomat Göran von Otter, as well as to members of the Roman Catholic Church including contacts to Pope Pius XII in the Vatican, in an effort to inform the international public about the Holocaust.
His story is told in the 2002 film co-written and directed by Costa-Gavras which I have reviewed here.
You can read more more Gerstein himself on this Wikipedia page.
To put the character and the events in some context, one should know something about the Holocaust itself and I have reviewed a book on the subject here.