@Arizona Docent: I agree, and IMO this is by far the best orangutan enclosure I have seen in person (and one of the best in photos). The space is big, but is made even larger and more dynamic with the vegetation, slopes, and ample climbing opportunities.
This is a wonderful photo and Saint Louis does so many things well that I personally think that perhaps only San Diego and Omaha could be placed higher in North America. When it comes to penguins, great apes, hoofstock, sea lions, insects, bears, reptiles, amphibians, pachyderms, birds and just about everything else one can imagine...Saint Louis is a phenomenal zoo that is amongst the very best of its kind in the USA....if not worldwide.