The Great Barrier Reef of Australia is an extensive complex of islets, shoals and, of course, coral reefs. It is located off of Australia’s northeastern coastline in the Pacific Ocean. The Reef expands over 1,250 miles to the northwest-southeast, at about 10 to 100 miles offshore, and is about 135,00 square miles in area. This wonder has been characterized as the biggest structure that living creatures have ever built. There are actually 2,100 reefs and 800 fringing reefs around the Great Barrier Reef. All of the reefs, however, share a common origin. They have all been formed from the skeletal waste and skeletons of a living marine organism mass over the course of millions of years. The framework of the reef is formed from tiny creatures’ calcareous remains, which are known as hydro corals and coral polyps, and bryozoans and coralline algae are what holds it all together. At the Great Barrier Reef, at least 300 different species of hard coral, worms, sponges, anemones, crabs, prawns, crayfish, lobsters, gastropods, and a wide variety of other fish, as well as birds, can be found. The crown-of-thorns-starfish is actually the reef’s most destructive animal, which has decreased the attraction and color of much the reefs due to feeding on a lot of the coral that is alive.