Even if the sum of the available information were only the aerial photos, what has been found so far in this analysis could be considered quite important. It has established an objective base for the survivor accounts in the photographic data. Thus the written descriptions and the modeling and maps can be substantiated by features visible on the aerial images. The method is not absolute, but rather depends on a convergence of evidence. There exists, however, a picture taken by Kurt Franz, the deputy Commandant of Treblinka, which is unique: the only extant picture containing images of an Aktion Reinhard gas chamber. This picture has been widely published as showing one of the excavators used at Treblinka for digging the burial pits and later for opening and removing the corpses for burning. In the background of this picture are the old and new gas chambers. Only a portion of the gable end roof of the new chambers is visible, but the last third of the older building is clearly evident.
All the factors determined from the Franz photograph were used to expand what could be inferred about the killing facilities. Since there was a security fence running north on the east side of the buildings, one could conclude that it must have served to prevent victims from attempting to escape from the killing site - an inconvenience to the SS who would have had to run them down in around the burial pits and burning grates. This fence line would entail placing gates to allow the dead to be removed by 'Sonderkommando' details. The purpose of the gate (Annotation 2) was to permit continued passage along the access road into the 'Totenlager'.
The photograph in Figure 36 was subjected to the same sort of measurements and graphical analysis described above in the section about the living camp. Measurements were made to determine the angular separation to all of the features of interest, and these were then