One of the largest problems facing the murderers was what to do with the bodies. Gassing was no problem, but the system was often overloaded by the sheer number of corpses, thus slowing the entire process. Cremation, rather than burial, was their solution, but even then the ashes had to be disposed of with some care. Large pits, like the one here, were used to dump the last vestiges of many people.
Just over the fence are foundations, all that is left of Canada, camp slang for a place of plenty. It is where the Jews' possessions taken off the transports were sorted, stored and eventually shipped, mainly to Germany.