How do we know that the gas chamber in Auschwitz I (the Main Camp) is authentic and not a fake created for tourists?
Holocaust deniers claim:
The Auschwitz-Birkenau State Museum officials have confirmed that the gas chamber in the Main Camp (Auschwitz I) is a “fake” created to be “shown to tourists.”
The facts are:
The crema/gas chamber in the Main Camp (Auschwitz I) has been accurately restored to its historic role as a gas chamber. It is meant to be a memorial and symbolic representation of all the cremas/gas chambers in the Auschwitz-Birkenau camp complex.
In January 1995, L’Express, a French news magazine, marked the 50th anniversary of the liberation of Auschwitz-Birkenau with an article about preservation challenges at both the Main Camp (now the Auschwitz-Birkenau State Museum) and Birkenau. Eric Conan, the author, noted that the current crematorium building in the Main Camp had been restored after the war to the appearance it had had when it was used as a gas chamber in 1941/1942.
David Irving, who the High Court of London in 2000 declared to be a Holocaust denier, racist and antisemite, hailed the article as a breakthrough: “L’Express has admitted that the gas chamber shown to tourists at Auschwitz is a fake–built by the Polish Communists three years after the war.”
Crema 1 in the Main Camp during the war.
Originally Crema 1 was equipped with two (later three) cremation ovens with a morgue room behind them. In late 1941 the morgue room in Crema 1 was sealed up and five holes were punched in the roof. The holes were capped with small chimneys through which the Zyklon-B was dropped. A large fan was also installed and the door was made gas tight.
On February 15, 1942, the first transport of Jews from Upper Silesia was gassed in Crema/Gas Chamber 1. The gassings continued until the fall of 1942 when the murder operation was moved out to Birkenau.
When the building was changed into an air raid shelter in 1944, the ovens were dismantled and the holes in the ceiling were filled in. The rooms were subdivided with strong walls to support the ceiling and contain the effects of a direct hit by a bomb.
Crema/Gas Chamber 1 after the war.
After the war, when the Main Camp was turned into a museum, the authorities felt that a crematorium/gas chamber was required at the end of the memorial journey for visitors. However, the four main cremas/gas chamber buildings, where most of the mass murder of the Jews took place, lay in ruins in Birkenau three miles away. Therefore, the Museum authorities restored Crema/Gas Chamber 1 according to blueprints dated September 25, 1941 and eyewitness testimony to speak for the existence of all the cremas/gas chambers at Auschwitz-Birkenau.
The chimney for the crematoria ovens, the gas chamber room, the doors, two of the three ovens were rebuilt, and four of the openings in the roof which had been used to pour in the Zyklon-B were restored.
There is the eyewitness testimony of German perpetrators about the use of Crema 1 as a gas chamber.
Pery Broad, a member of the Gestapo in Auschwitz-Birkenau, was captured by the British after the war. Broad wrote a detailed report on Auschwitz-Birkenau in which he described the first gassing in the Main Camp. Broad detailed how Jews from one transport were herded into the former morgue room where they expected to get showers: “The covers had been removed from the six holes in the ceiling . . . With a chisel and hammer they [the SS] opened a few innocuous looking tins . . . filled to the brim with blue granules the size of peas. Immediately after opening the tins they were thrown into the holes which were quickly covered.”
Hans Stark, also a member of the camp’s Gestapo unit, gave evidence at the Auschwitz-Birkenau trial in Frankfurt in 1963. He testified that gassings were carried out “in a room in the small crematorium which had been prepared for this purpose.” Stark recalled that the roof above the gas chamber room was flat with openings through which Zyklon-B in granular form was poured. On at least one occasion Stark himself poured the Zyklon-B in the holes. Stark recalled that the Zyklon-B “trickled down over the people as it was being poured in. They then started to cry out terribly for they now knew what was happening to them . . . After a few minutes there was silence. After some time had passed, it may have been ten or fifteen minutes, the gas chamber was opened. The dead lay higgledy-piggledy all over the place. It was a dreadful sight.”
There is the eyewitness testimony of survivors about the use of Crema 1 as a gas chamber.
Filip Müller, a Slovak Jew who arrived in Auschwitz-Birkenau in April 1942, was put to work as an oven stoker in Crema/Gas Chamber 1. One of Muller’s jobs was to drag the corpses from the gas chamber to the ovens. Later, he was transferred to Birkenau to work in the crematoria and burning pits there. Müller gave a detailed description of the process of murder in Crema/Gas Chamber 1: “When the last one had crossed the threshold, the SS leaders slammed shut the heavy iron-studded door which was fitted with a rubber seal, and bolted it . . . the Unterführers on duty had gone onto the crematorium roof . . . They removed the covers from the six camouflaged openings. There, protected by gas masks, they poured the green-blue crystals of the deadly gas into the gas chamber.”
There is physical evidence that Crema 1 was used as a gas chamber.
A rigorously conducted and authorized forensic study of the gas chambers done in 2000 found physical and photographic evidence of five holes that had been in the roof of Crema/Gas Chamber 1 and had since been sealed up. In the restoration four of the holes were re-opened and capped with wooden chimneys as they had been when Crema 1 was a gas chamber. Adam Zlobnicki recalled the restoration of the holes in the roof: “Those who reconstructed them had an easy task because the erstwhile introduction holes had distinct traces . . . Thus, they constructed in the same places again the openings for the little chimneys.” The fifth hole was not reopened.
Crema/Gas Chamber 1 in the Main Camp is not a “fake” but a space accurately restored to its historic role as a gas chamber. It is meant to be a memorial and symbolic representation of all the cremas/gas chambers in the Auschwitz-Birkenau camp complex.
 Eric Conan, “Auschwitz: La mémoire du mal,” L’Express, 19 Janvier 1995 at www.fpp.co.uk/Auschwitz/docs/Conan.html. See also Robert Jan van Pelt, The Van Pelt Report “(XI Irving Adrift [1993-1998]”) at https://hdot.org.
 Robert Jan van Pelt, The Van Pelt Report (“XI Irving Adrift [1993-1998]”) citing David Irving, “L’Express: ‘Tout y est faux” – Everything About it is a Fake, French Make a Clean Breast: Admit Forty-seven Year Auschwitz ‘Gas chamber’ Fraud,” Action Report #9, May 1995.
 Franciszek Piper, “Gas Chambers and Crematoria” in Yisrael Gutman and Michael Berenbaum, Anatomy of the Auschwitz Death Camp (Indiana University Press and United States Holocaust Memorial Museum, 1994), p. 159.
 Robert Jan van Pelt, “A Site in Search of a Mission” in Anatomy of the Auschwitz Death Camp (Indiana University Press and United States Holocaust Memorial Museum, 1944), p. 145.
 Deborah Dwork and Robert Jan van Pelt, Auschwitz: 1270 to the Present (W.W. Norton, 1944), pp. 363, 364.
 Filip Müller, Eyewitness Auschwitz: Three Years in the Gas Chamber (Ivan R. Dee, 1979), p. 38.
 Daniel Keren, Jamie McCarthy, and Harry W. Mazal, “The Ruins of the Gas Chambers: A Forensic Investigation of Crematoriums at Auschwitz I and Auschwitz-Birkenau,” Holocaust and Genocide Studies, 18(1), Spring 2004 at https://phdn.org/archives/holocaust-history.org/auschwitz/holes-report/holes-intro.shtml. See “Part IV: The Zyklon Introduction Holes in Crematorium I.”