The roll-call area was at the heart of the concentration camp. Prisoners had to assemble here two or three times a day.
Just like the commandant's office, this square did not always look the way it does now. Due to the camp being expanded in stages, the roll-call area was not properly paved until 1942.
Take a look at the historic photograph showing the paving of the roll-call area. The photo was taken in 1941/42 by the Erkennungsdienst.
Although the photo at hand shows the extensive amount of labour and indicates that all the structures had to be built by the prisoners, it does not depict the extreme suffering of the prisoners carrying out the work. The SS did not want the crimes committed in the camps to be shown in photos.