Great Barrier Reef

The Great Barrier Reef lies off the northeastern coast of Australia and is both a scientific wonder and an increasingly popular tourist attraction. It has been described as "the most complex and perhaps the most productive biological system in the world." The Great Barrier Reef is the largest structure ever made by living organisms including human beings, consisting of the skeletons of tiny coral polyps and hydrocorals bounded together by the soft remains of coralline algae and microorganisms.