How were there 2.7 million Jews killed in 1942 alone at death centers? At Auschwitz-Birkenau there was only one crematorium built until 1943, when another three were built and completed. 1942 was apparently the most intense period of the holocaust even though Auschwitz-Birkenau only had 1 crematorium built at the time. Where did the mass graves of jews disappear then?? Cremation of 2.7 million jews is obviously ludicrous and outlandish to even think of.