Content created by Professor Deborah Lipstadt in conjunction with Maureen MacLaughlin and Dan Leshem. CLAIM: Holocaust deniers argue that if there were no holes in the roofs then the structures were not gas chambers and Auschwitz was not an extermination camp. If Auschwitz was not an extermination camp, then the Holocaust did not happen.

RESPONSE: However, extensive evidence of the gas chambers in Auschwitz-Birkenau remains. Cremas 2 and 3 had holes in the roof for the introduction of Zyklon-B into the gas chamber below. Eyewitness and photographic evidence documents these holes, and a recent study has proved their precise location.