This is the roof of the
underground gas chambers of Crematorium II. In the days of its
use, the concrete was covered with grass turf. Inside, there
were two gas chambers
separated by an airtight door. The back chamber, here in the
foreground, was used for gassing people from smaller transports.
The low structure to the right is the area behind the five furnaces
where the ventilations system and single chimney were.