Hannover wrote:
Below is the alleged mass grave at Treblinka.
Correction:
Below is [ONE OF] the [MANY] alleged mass grave[S / CREMATION PITS] at Treblinka II.

The very best website that helps one to understand the issue of the alleged "huge mass graves" at Treblinka is this site here:
http://www.thisisaboutscience.com/and particularly this link here:
https://vnnforum.com/attachment.php?attachmentid=10150&stc=1&d=1524529600which shows the following annotated photo:

The photo above is of the alleged "huge mass grave" G36 (as per CSC) / #15/100 (as per thisisaboutscience.com)
Please notice two things in said photo:
CSC herself refers to the "huge mass grave" as a "
probable burial / cremation pit" and the stones do not actually cover alleged "huge mass grave" G36 / #15/100.
Edited to add:
It is extremely important to note that CSS, in a map that she made herself here:

in which she labeled all the "
probable grave sites" - didn't even include G36 / #15/100 as one of the alleged "probable grave sites."
Also note that in these CSC photos:

CSC refers to "huge mass grave" G36 / #15/100 as a "
probable pit identified though geophysical survey."
So, for those keeping track, CSC does not even mention "huge mass grave" G36 / #15/100 in her "
probable grave site" map and refers to it as a "
probable burial / cremation pit" in one instance and a "
probable pit identified though geophysical survey" in another.