Great Barrier Reef
Any trip to australia should include a trip to wonder of the world - the Great Barrier reef.
You can choose to stay on the reef at several island resorts or simply do a day trip on one of the many licensed boats that visit the reef daily - weather permiting of course.
Most trips will include all you need to view the reef (snorkels, goggles and flippers) and others will have glass bottom boats and diving facilities.
The island resorts can give you access right off the beach and are accessible from as far south as the Gold Coast. That's right - you can do a day trip to the reef from the Gold Coast and be back in your hotel by 6pm that night.