Here is an aquarium that appeals to young and old alike. No fewer than 12 000 aquatic animals of 650 different species are kept in tanks designed to recreate their actual marine biotopes, in particular those of the Great Barrier Reef and Sydney Harbour. The star attractions are the Shark Walk, a 165m tunnel submerged at the bottom of a tank housing sharks, rays and Queensland groper, and an immersive "penguin expedition" by boat.