This is one of the world's best aquariums and should be near the top of your itinerary. The main attractions are the underwater walkways through two enormous tanks -- one full of giant rays and gray nurse sharks and the other where you can see the seals. The sharks get fed at 2pm daily. Other exhibits include a magnificent section on the Great Barrier Reef, where thousands of colorful fish school around coral outcrops. Sit on the steps beside the huge, main Barrier Reef tank, listening to the classical music, and you might never want to leave. Also on display are two saltwater crocodiles and some fairy penguins. A touch pool allows you to stroke baby sharks. The Mermaid Lagoon features two dugongs (or sea cows). Try to visit during the week, when it's less crowded. Allow around 2 hours. Tickets are a little cheaper if bought through the website.