How big is the Great Barrier Reef?
The Great Barrier Reef is the world's largest coral reef system, stretching more than 2,300 kilometres along the Queensland coast. The Great Barrier Reef Marine Park covers about 344,400 square kilometres.
The reef is not a single structure but a collection of about 2,900 individual reefs and around 900 islands. It extends from the tip of Cape York in the north to near Bundaberg in the south.
The marine park is larger than the United Kingdom, Switzerland and the Netherlands combined. It was declared a World Heritage area in 1981.
A living structure
The reef is built by tiny animals called coral polyps, which create hard skeletons of calcium carbonate. Over thousands of years, these skeletons have formed massive reef structures.
The reef supports an extraordinary range of life, including more than 1,500 species of fish, hundreds of types of coral, sea turtles, dugongs, sharks and whales.
The Great Barrier Reef faces threats from climate change, coral bleaching, crown-of-thorns starfish outbreaks and poor water quality. Scientists monitor its health closely.
Tourism linked to the reef supports tens of thousands of jobs in Queensland, with Cairns, Port Douglas and the Whitsundays as the main gateways for diving and snorkeling trips.