After the Eastern State Pen was closed, cats took over. There were so many, the animal shelters were sent in to spay and neuter the cats due to the massive overpopulation. Eventually the cats died out and this artistic installation (there are cat statues everywhere here) was placed as a tribute to the cats.
I found this guy (down to the left) in a cellblock not open to the public. I stuck my camera lens through the bars to to get the shot.