I've been to 8 zoos/zoo-type establishments in my life. Both Chicago area zoos multiple times. They were both always a blast and Lincoln Park is free, so that was always cool.
I've also been to the Milwaukee Zoo twice. I prefer it to the Chicago area zoos because I think it's structured better.
I've also been to Zoo Boise, which is a cute small zoo in Boise, Idaho, where I go to school these days. The snow leopard is adorable. He has social anxiety so he stretches out against the glass, puts his tail in his mouth and covers his eyes.
I've also been to Sea World San Antonio and San Diego. I don't remember much from either.
I've also been to the San Diego Zoo, which is one of the coolest places on the freaking planet.
Oh, and I visited a place called Reptile Gardens in Rapid City, South Dakota once. It's the largest reptile reserve in the world. It's remarkable. Also, a relatively hidden gem, seeing as it's in rural South Dakota and often overshadowed by Mount Rushmore.
If you can't tell, I'm a bit of a zoo enthusiast. I've always loved exotic animals, and zoos are the easiest way to see them.