• The Great Barrier Reef is the largest among the living structure on the Earth. • It is a site of the remarkable variety and beauty on the north-east coast of Australia. The reef is situated off the coast of Queensland, Australia, in the Coral Sea. • It comprises the world's largest collection of coral reefs, with 400 types of the coral, 1,500 species of fish and about 4,000 types of mollusc. It even holds great scientific interest as the habitat of species like the dugong (i.e. sea cow) and the large green turtle, which are threatened with extinction. • The reef, which is large enough to be visible from the space, is made up of nearly 3,000 individual reefs. Majority of the Great Barrier Reef is a marine protected area, managed by the Great Barrier Reef Marine Park Authority of Australia.