These are church bells (built in 1508 and 1668) which were destroyed in 1942. It is told that they rang a last time moved by the firestorm during the bombardment. They were left in the place where they fell down as a memorial.
Thank you all for the comments! Indeed the memorial was very poignant (a new word in my active vocabulary now - thanks Tony!), and I tried to capture this. I varied aperture (for reasonable DOF) and exposure time (limited by pressing the Rollei 35 S to the iron bars surrounding the memorial, if I remember correctly it was something between 1/8 and 1/2 sec) - this was the best one of three negatives.