Aquariums are a must for ocean lovers. Yes, Sydney's Sea Life Aquarium is located in the touristy hub of Darling Harbour, but the unique species and ecosystems that you can view make it hard to pass up. Take Dugong Island, an underwater shipwreck where the world's only pair of dugongs—relatives of elephants—play and wade, for example. These two, Pig and Waru, are rescued orphans that can't be re-released. Other unique Australian creatures on display include weedy sea dragons, little penguins, hard-to-spot platypi, a giant Queensland grouper, and the gray nurse sharks that stalk prey in Shark Alley.