Which famous marine World Heritage site is home to 400 species of coral and 1,500 species of fish?

The Great Barrier Reef, off the coast of Queensland in northeastern Australia, is the largest living thing on Earth, and even visible from outer space. The 2,300km-long ecosystem comprises thousands of reefs and hundreds of islands made of over 600 types of hard and soft coral. It's home to countless species of colourful fish, molluscs and starfish, plus turtles, dolphins and sharks.