Photo of the old Milan Zoo. I think this was the sea lion pool. To give an idea of scale, the gap beneath the island is about 30cm (1foot). There is some footage in the video (link below) of sea lions trying to swim in it.
I believe the zoo closed in 1992, apparently homeless people moved into the zoo cages after the animals were moved out.
Below is a link to a poorly translated page which features a bit of film footage of the zoo.
http://translate.google.co.uk/translate?hl=en&sl=it&u=http://it.wikipedia.org/wiki/Giardini_pubblici_Indro_Montanelli&prev=/search%3Fq%3DVasca%2Bdelle%2BFoche%2Bal%2BVecchio%2BZoo%2Bdi%2BMilano%26biw%3D1024%26bih%3D590
