The Great Barrier Reef is the largest system of coral reef in the world, stretching more than 3000 kilometers (1,900 miles). It is the only reef on Earth that can be seen from space and is the world’s biggest single structure made by living organisms. The reef structure is composed of and built by billions of tiny organisms. The Great Barrier Reef also features a host of wildlife including green sea turtles, dolphins, whales, sea snakes and clown fish.
(Source: pacifism, via clingy)