Omaha's Henry Doorly Zoo & Aquarium

The world's largest indoor desert? Check. The world's largest nocturnal exhibit? Check. America's largest indoor rainforest? Check. An aquarium showing habitats from the Arctic to coral reefs? Check, yet again. The superlatives say it all. You could easily spend an entire day wandering through this massive and well-crafted complex, which is frequently named the best zoo in America. Optional animal encounters can be arranged if you pay extra.