One of the longest-running attractions on The Strip, Shark Reef at Mandalay Bay combines a marine petting zoo with underwater exploration. Visitors walk down two glass tunnels through an impressive menagerie of animals including golden crocodiles, sea turtles, jellyfish, and Komodo dragons. The highlight is a mesmerizing shark exhibit, complete with sunken pirate ship, where the sharks swim on all sides, including the floor. Tickets are $18.