NASA photo of the Great Barrier Reef
The Great Barrier Reef is located at the northeast edge of Australia's continental shelf. It is comprised of 3000 separate reefs that started growing about 200,000 year ago. There are 350 species of coral. The Barrier Reef attracts thousands of tourists each year. Half of the Reef is protected from fishing.
Related reading: What is a Coral Reef Made of?; Are Corals Animals or Plants?