I think Pairi Daiza's white tiger enclosure.
While many don't think it's a good enclosure, I don't think it deserves so much hate as being said here.
The enclosure is located in a beautiful Cambodian temple (Angkor temple) which is made of real hard lava from the Merapi volcano, located in Java. It offers several great viewing perspectives for visitors, which don't seem to bother the tigers, as I have never seen them behaving stereotypically behaviour and they are always sleeping in the shade or on the steps of the temple, which indicates that they are not stressed, because you don't sleep with many people watching you, do you? They also have a big pool. There are only 2 tigers (brother and sister named Sanka and Mumbai), and for them, the enclosure is not too bad in size for them.
The enclosure was originally smaller, which can be seen in the enclosure. The enclosure consists of 2 parts: the rectangular section with stairs and the pool. The 2nd part is behind the first rectangular part and is square and is mainly only viewable from above. Between these 2 areas is a glass wall with a door, which is always open. You can see from this that it was not normally intended that both areas were accessible to tigers, the square area was originally for clouded leopards, which now have a smaller but probably better habitat in a greenhouse in the Chinese part. If the tigers only had the front rectangular section, the enclosure would certainly have been too small, but now it is not so bad.
However, I totally agree that in 1 or more corners of the enclosure (and believe me, there are many) could use more (large) plants, like bamboo. Also a large branch for them to climb on would be welcome.
However, Pairi Daiza goes to great lengths to keep the tiger occupied, so this compensates a bit for the near lack of plants.
The enclosure is now average in my opinion, but Pairi Daiza knowing it could have been so much better.