yeah - you can see the remnants of the original building from the older looking roof - i believe the windvane is still on top there .. there were train tracks that ran a separate line behind the laboratory, and yes - the octagonal shape i believe is the foundation for the tower that was blown up by the US Army in 1917 (they were worried that the Germans might use it either for a landmark for their submarines or as some sort of communication device) .. it was rumored that it took multiple attempts to actually destroy the tower given the solid construction and size of the wooden beams that were used.
It looks like much of the connecting area between the laboratory and the tower where the tunnels/connections should be are now filled in .. presumably AGFA was dumping their toxic photographic chemicals there - i guess filling it all in with cement constitutes their long cleanup ..