Context: The film is concerned chiefly with four topics: Chemno, where mobile gas vans were first used by Germans to exterminate Jews; the death camps of Treblinka and Auschwitz-Birkenau; and the Warsaw Ghetto, with testimonies from survivors, witnesses, and perpetrators. The sections on Treblinka include testimony from Abraham Bomba, who survived as a barber;[5] Richard Glazar, an inmate; and Franz Suchomel, an SS officer who worked at the camp, who reveals intricate details of the camp's gas chamber. Bomba breaks down while describing how a barber friend of his came across his wife and sister while cutting hair in an anteroom of the gas chamber. Suchomel states he did not know about extermination at Treblinka until he arrived there. This section includes Henryk Gawkowski, who said he drove one of the transport trains while intoxicated with vodka. Gawkowski's photograph appears on the poster used for the film's marketing campaign. Testimonies on Auschwitz are provided by Rudolf Vrba, who escaped from the camp before the end of the war; and Filip Muller, who worked in an incinerator burning the bodies from the gassings. Muller recounts what prisoners said to him, and describes the experience of personally going into the gas chamber: bodies were piled up by the doors 'like stones'. He breaks down as he recalls the prisoners starting to sing while being forced into the gas chamber. Accounts include some from local villagers, who witnessed trains heading daily to the camp and returning empty; they quickly guessed the fate of those on board. Lanzmann also interviews bystanders. He asks whether they knew what was going on in the death camps. Their answers reveal that they did but they justified their inaction by the fear of death. Two survivors of Chemno are interviewed: Simon Srebnik, who was forced to sing military songs to entertain the Nazis; and Mordechai Podchlebnik. Lanzmann also has a secretly filmed interview with Franz Schalling, a German security guard, who describes the workings of Chemno. Walter Stier, a former Nazi bureaucrat, describes the workings of the railways. Stier insists he was too busy managing railroad traffic to notice his trains were transporting Jews to their deaths. The Warsaw ghetto is described by Jan Karski, who worked for the Polish government-in-exile and Franz Grassler, a Nazi administrator who liaised with Jewish leaders. A Christian, Karski snuck into the Warsaw ghetto and escaped to England to try to convince the Allied governments to intervene more strongly on behalf of the Jews, but failed to do so. Memories from Jewish survivors of the Warsaw Ghetto uprising conclude the documentary. Lanzmann also interviews Holocaust historian Raul Hilberg, who discusses the historical significance of Nazi propaganda against the European Jews, and the Nazi development of the Final Solution. The complete text of the film was published in 1985. The man in the poster[edit] During his trip to Poland in July 1978, Lanzmann's crew filmed his conversations with an elderly Polish man by the name of Henryk Gawkowski, who, some 35 years earlier, had worked on the locomotives pulling Holocaust trains to Treblinka during World War II.[6] The photograph used for the film poster shows Gawkoski on a locomotive to Treblinka, but there was no reconstruction of events from his youth: the type of locomotives used in 1943 were different, as was the landscape. The female translator insists on calling him the train's operator (or conductor in Polish); nevertheless, Gawkowski informed that he only shoveled coal into the engine's firebox, and that two German officers were always on every train. What happened to the victims, Gawkowski said, was not his fault, adding emphatically that if he had the opportunity, he would have been the first to slash Hitler's throat.[6] 
 Question: What were some of director Claude Lanzmann's interviews of his subjects filmed in?
Output: holocaust