An architecture group hosted a competition for designs of a "vertical zoo" that they wanted to propose for Buenos Aires. Have fun looking at this and please try to keep your screaming down. You have neighbors, after all ::: Arquitectum 2010::: Publications
It's MAD. BTW, if you ever come to BA, visit Constanera Sur. Right in the middle of BA there is a reserve with many zoo staples living in the wild: wild guinea pigs, coypus, monk parakeets, southern screamers, wood rails, maguari storks, assorted herons and waterfowl. Over 100 species of birds can be seen in a day. I must say that, luckily, these mad projects would sink into the muddy soil, and no longer spoil the place.