Australia is a country made up of the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area. Australia is one of the world’s premier diving destinations, with a variety of types of scuba diving available for all levels of experience. Australia is a great choice for diving because it has colorful sea life, a selection of beautiful dive sites, and interesting underwater topography. Types of diving available in Australia include reef diving, wreck diving, diving with a variety of sharks and other marine life, and viewing the kelp forests, as well as some of the finest freshwater cave diving in the world. The depth at Australia's dive sites varies from 5-40m/16-131ft. The coral reefs are shallow and most of the dive sites are between 10-20m/33-66ft deep. Australia has more than 300 dive sites. The main diving areas are New South Wales, Queensland, Southern Australia, Western Australia, and Victoria. The most popular is the beautiful city of Cairns, the start point for most of the liveaboard trips to the Great Barrier Reef; other great diving destinations include Lady Elliot Island, Brisbane. The Great Barrier Reef is the largest reef system found anywhere in the world and is the clear highlight of diving in the region of Australia. The reef itself is a collection of over 900 islands and over 3,000 separate coral systems, housing over 400 types of coral and 1,500 different varieties of fish. Dive sites such as the SS Yongala and Ningaloo reef are some of the best in the world. Diving in Australia is an experience you will never forget.