This picture shows part of the wall that surrounded the concentration camp. There are several layers of protection against escape. Starting from the outside working in, there is the outer wall, a wide path of gravel, an electric fence, and a cement ditch. Guard towers, such as the one here, were dotted along the fence. The wide grass path that fills the right side of this picture was off-limits to all inmates. Anyone caught on the grass would be shot on sight.