Is the Great Barrier Reef the World's Largest Living Thing?

No. The Great Barrier Reef is not a single organism but a complex ecosystem comprising over 2,900 individual reefs and 900 islands. It is built by countless coral polyps—tiny colonial animals that secrete calcium carbonate skeletons. Over millennia, these skeletons accumulate into massive reef structures. The Great Barrier Reef is the largest coral reef system on Earth, stretching >1,400 miles along Queensland, Australia.