The Great Barrier Reef is the world’s largest coral reef system, composed of roughly 3,000 individual reefs and 900 islands that stretch for 2,600 kilometres and cover an area of approximately 344,400 km².

Located in the Coral Sea, off the coast of Queensland in northeast Australia, the Great Barrier Reef is a World Heritage eco holiday destination, with a range of environmental tourism operators available providing educational and interpretive information on the reef. The Great Barrier Reef is made up of many millions of tiny organisms, known as coral polyps. Corals belong to the group of animals (Cnidarians) that also include anemones, jellyfish, bluebottles and hydroids and the coral polyp is a small tube-like structure, with a central space opening via a mouth. Most corals also contain zooxanthellae (pronounced zo-zan-thel-y), a single-celled algae that live inside the coral animal and help to supply it with food.

The coral reefs of the Great Barrier Reef are an accumulation of dead corals and other organisms with a limestone skeleton, cemented together by some algal species and by physical processes. Selected as a World Heritage Site in 1981, the Great Barrier Reef can be seen from space.

• 30 species of whales, dolphins and porpoises that live in, or visit Great Barrier Reef waters;
• some of the largest populations of dugongs in the world live on the Great Barrier Reef;
• over 200 species of birds (including 40 species of seabirds);
• 6 breeding species of sea turtles;
• 14 species of sea snakes;
• 1500 species of fish;
• 5,000 species of molluscs;
• 400 species of coral
• 500 species of seaweed or marine algae; and
• 15 species of seagrass.