Great Barrier Reef is the largest coral reef in the world, also, it is the largest organic construction on Earth. It stretches for 1,250 mi (2,000 km) in the Coral Sea, off the coast of Queensland, Australia. The Great Barrier Reef is actually a series of individual reefs separated from the mainland by a shallow lagoon. The reef is extremely beautiful and attracts thousand of tourists a year, which threatens to harm the delicate eco-system of the reef and its unusual marine life.
The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms. This reef structure is composed of and built by billions of tiny organisms, known as coral polyps. It supports a wide diversity of life and was selected as a World Heritage Site in 1981. CNN labeled it one of the seven natural wonders of the world. The Queensland National Trust named it a state icon of Queensland.