Bring their friends ;D
The 14yo was the one that wanted to go to the zoo. If they have any particular interests or excursion preferences that's what we do if I can afford it.
I think any zoo or aquarium worth their salt has to be a centre for education and conservation these days. Having a horrible past doesn't mean they can't have a useful present and future, and I think anything that helps improve understanding and education for future generations of everything is good :)
Who doesn't love meerkats ;D
I'm sure there are some people that don't love meerkats but so far everyone seems to think they're cute XD