Indeed, if all three descriptions were exactly alike, we might suspect that the later account was copied from the earlier ones. Because they are not, we know that here are three separate eyewitnesses to these items. Holocaust-deniers reject the validity of the aerial photographs, claiming that the four dark spots on the roof of each gas chamber were retouchings added by the CIA or some other conspiracy. John Ball, who has no expertise in interpreting aerial photographs, suggests either that hypothesis or, alternatively, that the dark spots were flowerpots sitting on each gas chamber. The objects shown on the roof in the ground photo, say some deniers, are ordinary boxes of construction material.
Deniers also claim that there is no evidence of four holes in the roof of each gas chamber.
Because the chambers were dynamited in an attempt to hide evidence of mass murder from the approaching Soviet army, the roofs have collapsed and it is difficult to tell in the rubble what is a hole and what is not. Later this year, an essay on this website will address this question in detail. As obvious evidence of their crimes, the latter would have been removed by the Nazis from the gas chambers before they were blown up. Ludicrously, deniers show photos of the solid columns as proof that the wire-mesh columns never existed. Such feeble attempts to rewrite history do not stand.