Density of Corpses in the Graves
Karl Alfred Schluch, a former member of the SS staff of Belzec extermination camp, described one of the graves in that camp as follows:
The size of a pit I can only indicate approximately. It should have been about 30 meters long and 20 meters wide. The depth is difficult to estimate because the side walls were at an angle and on the other hand the earth taken out had been piled up at the edge. I think, however, that the pit may have been 5 to 6 meters deep. All in all one could have comfortably placed a house inside this pit. 
Schluch’s description roughly matches the measurements of the larger among the Belzec mass graves (see Table 7.1), but what is especially noteworthy is the impression that the size of the pit described made on the witness: he remembered it as a pit so large that one could have comfortably placed a house inside. Elementary common sense tells us that who makes graves this big a) does so because he needs them to bury large numbers of bodies and b) intends to use them to the maximum of their capacity. Especially when all known evidence shows that this was what the graves at Belzec and the other Nazi extermination camps were made for and how they were used – evidence including but not limited to vivid eyewitness descriptions like the following from Sobibor extermination camp:
The first grave had been covered with a layer of sand. As this grave was completely full, the other bodies had to be taken elsewhere, even though the new grave was not yet ready. I still clearly remember arriving for work at the second grave one morning, to find that the bodies which had already been piled up along one side had decomposed to such an extent that in the sweltering heat blood and body fluids had run all along the bottom of the unfinished grave. It was clear that we could not continue to work under such circumstances. I remember giving directions to build a kind of bank, about 30 cm high perhaps, right across the bottom of the grave. Ittner was there as well; I spoke to him about it. In this context I can also give an impression of the extent of deterioration of the bodies in the first grave. The layer of sand covering the grave cracked and rose up to the point where some of the bloated bodies were being pushed to the surface, rolling out sideways. So I had the Arbeitsjuden build a proper sand bank all around the grave. The sight of it all was intolerable, and the stench also unbearable.
Mattogno, Graf & Kues disagree with elementary common sense. In their book, the reasoning that enormous graves are made for enormous numbers of bodies is "fallacious" because "if there were no hundreds of thousands of corpses to dispose of, there would also exist no pressing need to save burial space," and there were "several documented mass graves that have a density of 1-2 corpses per cubic meter." To be sure, if there were no enormous numbers of corpses to dispose of, there would also exist no pressing need to save burial space. But what need would there have been, then, to create such an enormous amount of burial space in the first place? Why make gigantic pits like grave # 4 at Sobibor, which was 70 meters long, 20-25 meters wide and 5 meters deep and had a volume (corrected for sloping) of 6,819.80 m³, when a few much smaller and more shallow graves would have been sufficient to dispose of the camp’s mortality?
The "several documented mass graves that have a density of 1-2 corpses per cubic meter" were the three graves found by Soviet investigators at Treblinka in August 1944, with the dimensions 10x5x2, 10x5x1.9 and 10x5x2.5 meters. Only one of these graves was a little deeper than the proverbial "six feet below ground", and this grave – the biggest of the three – had a volume of merely 125 cubic meters, i.e. it was about 55 times smaller than Sobibor grave # 4. People may make relatively small graves in order to toss a relatively small number of bodies inside, but who would expend the time, effort and resources required to dig five meters below ground and make a grave with a volume of 6,819.80 m³, only to then squander the grave space so laboriously created by burying corpses at a density of no more than 1-2 corpses per cubic meter? According to Alex Bay, a pit 50 by 25 meters with a volume of 8,500 cubic meters would "require weeks or months to dig by manual methods using picks, shovels, and wheelbarrows, depending on the number of laborers available"; even with mechanical excavators "the time needed to complete these large pits would have been on the order of a two or three weeks." The time required for the 6,819.80 m³ of Sobibor grave # 4 would be a little but not much less.One might think that Mattogno, Graf & Kues would like their readers to believe that the SS made graves big enough for a house to comfortably fit in because they liked to keep their Jewish labor force digging all the time, or because they enjoyed the healthy exercise themselves or were so fond of handling excavators that they made enormous graves just for the fun of it.
 Deposition of Schluch, B162/208 AR-Z 252/59, Bd. VIII, f. 1504 ff, description of grave on f. 1513; cf. Kogon et al, Massentötungen, p.168. Translation from German and emphasis are by the author.
 Deposition of former SS-man Kurt Bolender in Hagen on 18.12.1963 (as note 29).
 MGK, Sobibór, pp.123f.
 On p.167 ff. of their Sobibór book, MGK treat their readers to an "estimate" whereby "the number of Sobibor victims is in the vicinity of 10,000" over a period of 16 months, i.e. ca. 600 per month. To bury 600 corpses at a density of only 3 per cubic meter (half the "maximum" concluded on by Ball according to Mattogno, and corresponding to the minimum density estimated by medical expert Mieczysław Piotrowski in an investigation of the Treblinka I labor camp’s mass graves in August 1946, see M&G, Treblinka, p.88), a mere 200 cubic meters of grave space would have been required. The volume of Sobibor grave # 4 alone (corrected for sloping) was 36 times larger.
 See note 85.
 Bay, Treblinka, ‘Reconstruction of the Death Camp (Continued)’.