Here is the central hub:

The hub has glass looking into the Sumatran Orang-utan exclosure and the Sumatran Tiger #2 underwater viewing area:

To the left there are unobstructed views into the left half of the Sumatran Tiger #2 enclosure:

(who can spot the tiger in this shot?)
To the right there are also unobstructed views into the Sumatran Orang-utan exclosure:

(If the tiger isn't doing much, just spend a couple of minutes changing to a wide angle lens and then within minutes the tiger will be performing. The only problem is by the time you've changed lens again, the tiger will have disappeared again.
Worked for me.

Daniel