Is the Great Barrier Reef classified as a natural or cultural site?

The Great Barrier Reef is the world's largest coral reef system, composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometers (1,400 miles) along the coast of Queensland, Australia. The Great Barrier Reef is classified as a natural site by UNESCO, as it is a unique and outstanding natural feature of the world.