It is a struggle to name more than a handful of major American zoos with 20 or more invertebrate exhibits. Certainly Cincinnati, Saint Louis, Omaha and Houston (all with excellent Bug Houses) but after that many major zoos in the USA have anywhere from 5-15 vivariums with invertebrates. It seems as if zoo enthusiasts have to venture forth to specialized 'Bug Zoos' in order to see an impressive amount of invertebrate diversity.