True but usually you have multiple documents, testimonies and material facts that you can compare for that simple reason that human memory fails. Some people sa

True but usually you have multiple documents, testimonies and material facts that you can compare for that simple reason that human memory fails. Some people say it was 100 meters on the left and some others it was 300 meters to the right etc... Also we know about other death camps - Sobibor, Plaszow, Treblinka - that they have evolved with time, procedures changed etc. With little material documents, lack of victims testimonies and lacking archeological research historians know way less that they would like to... Auschwitz is very well documented and there is plenty of testimonies. But Treblinka, Belzec and Sobibor less so... > The lack of viable witnesses who could testify about the camp's operation is the primary reason why Bełżec is not well known despite the enormous number of victims.[8] Israeli historian David Silberklang writes that Belzec "was perhaps the place most representative of the totality and finality of the Nazi plans for Jews". https://en.wikipedia.org/wiki/Belzec_extermination_camp https://en.wikipedia.org/wiki/Belzec_extermination_camp