The Great Barrier Reef is 1,429 miles long and runs along the coast of northeastern Australia. The Great Barrier Reef Marine Park covers about 132,819 square miles and contains about 3,000 separate coral reefs.
By contrast, the Belize Reef is only 186 miles long, even though it is the second-longest reef in the world. The Great Barrier Reef has almost 2,000 different species of fish. The reef has seen at least four glacial and interglacial cycles.
Some of the thousands of species that are native to the reef are now critically endangered. One-fifth of the reef has already been devastated. The main causes for depletion of the Great Barrier Reef include pollution, global warming and overfishing.