I love the Cleveland MetroParks Zoo. It's big, with a lot of mild hills and slants, in a shady and forested area. They have a petting zoo with farm animals (the miniature pony is cute), my favorite part - the aquarium (the stingrays and sharks are so neat), a rainforest with poisonous dart frogs (hard to believe something so small can be so deadly), and every other animal you can hope a zoo would have.
more