I really liked the Bogori-Wald ape house at Frankfurt Zoo which houses Orangs, Bonobos and Gorillas. The Orang area is the 2nd best I've personally seen after RORA at Chester, though my only slight criticism of Frankfurt would be that with the good height of the enclosure they could have perhaps included more vertical ropes than they have for brachiating.
This place looks like a film set. Were you to be shown the picture out of context (i.e. not in a zoo forum) most people would never imagine it was an animal enclosure - maybe a still from Raiders of the Lost Ark. Yet it must have cost a pretty penny all the same - and to what advantage (for the animals) ?
Although displaying tigers in the context of "abandoned ruins" isn't necessarily inaccurate....check out this lovely photo from Ranthambore Tiger Reserve in India