Robert Jan van Pelt, no friend to revisionists, wrote this:
There have been additions to the camp the Russians found in 1945 as well as deletions, and the suppression of the prisoner reception site is matched by the reconstruction of Crematory I just outside the north-east perimeter of the present museum camp. With its chimney and gas chamber, the crematory (KL/BW11 and KL/BW14) functions as the solemn conclusion for tours through the camp. Visitors are not told that what they see is a post-war reconstruction; its homicidal gas chamber had been abandoned in 1942, and at the end of 1943 the three furnaces were dismantled. Modified further in the fall of 1944, the building became an air-raid shelter with an emergency operating room. / When Auschwitz was transformed into a museum after the war, the decision was taken to concentrate the history of the whole complex in one of its component parts. The infamous crematories where the mass murders had taken place were ruins in Birkenau, a few kilometres distant. The committee felt that a crematory was required at the end of the memorial journey, and Crematory I was reconstructed to speak for the history of the four crematoria at Birkenau. This program of usurpation was rather detailed. A chimney, the ultimate symbol of Birkenau, was recreated; four hatched openings in the roof, as if for pouring Zyklon-B into the gas chamber below, were installed, and two of the three furnaces were remodelled. There are no signs to explain these restitutions, they were not marked at the time, and the guides remain silent about it when they take visitors through this “palpably intact” building that is presumed by the tourist to be the place where it happened.
He also quoted a historian by the name of Eric Conan who wrote this:
In 1948, when the Museum was created, crematorium 1 was reconstructed in what one supposed to be its original state. Everything there is wrong: the dimensions of the gas chamber, the locations of the doors, the openings for pouring in Zyklon B, the ovens that were rebuilt according to the recollections of some survivors, the height of the chimney. At the end of the 70s, Robert Faurisson exploited those falsifications all the better because at that time the Museum officials refused to admit them.
Both quoted in
The Van Pelt Report.