So there's a pile of mainly soil inside but which is much smaller than the structure. For a "death camp" which held up to 50,000 prisoners at a time and 150,000 through the entire war. Seems like that may have been an inefficient setup. Interestingly, the Majdanek "gas chamber" is the only alleged gas chamber with any of the Prussian blue staining characteristic of cyanide use. I don't know if I'd call that a mountain, but maybe it's the closest thing. Considering how much of it is soil, it's hard to say what sort of numbers that pile is supposed to represent. They probably do not claim that it represents the full 80,000 that is alleged. Although, the memorial was constructed by the Soviets, who alleged that ~1,500,000 were killed there, so perhaps it's supposed to represent much more than 80,000 bodies. I'm sure that between the typhus epidemic and food supply issues, many prisoners did die during the war. Many German POWs died of the same causes in American camps even after the war. Typhus especially is a persistent issue in these sorts of facilities, and even Ellis Island has a delousing chamber + crematorium setup, although no genocide is alleged to have taken place there. Whether you achieve these sorts of numbers in a camp of that population size is hard to say. But for the camps with much higher alleged figures, you really would have a literal mountain of ash. And there's nothing like this at any of the other camps.