Great Barrier Reef
The world's most extensive coral reef system, the Great Barrier Reef, extends along Queensland's east coast for over 2,300 kilometres from Bramble Cay in the Gulf of Papua to Lady Elliot Island northeast of Bundaberg. The Great Barrier Reef Marine Park Authority administers the 345,400-square-kilometre marine park, which, at its widest point, extends 400 kilometres east of Mackay.
The Barrier Reef includes around 3,000 reef systems and coral cays (2,100 individual reefs and 800 fringing reefs), 300 reef islands or sand cays, nearly one-third of which are vegetated, and numerous outlying continental islands. Today's reefs, sitting atop layers of reef and alluvium dating back over two million years, are about 8,500 years old, dating back to the end of the last Ice Age. They lie between 16 to 160 kilometres from Queensland's east coast and, and range from 60 to 250 kilometres in width. Core samples from structures associated with today's Reef suggest that reefs developed on Australia's continental shelf as early as the Miocene Epoch. Subsidence of the continental shelf has proceeded, with some reversals, since then.
European exploration of the reef began in the 18th century, when Louis-Antoine, Comte de Bougainville encountered its outer fringes on 4 June 1768. James Cook's Endeavour ran aground on a reef off Cape Tribulation on 10 June 1770.
Matthew Flinders began the work of charting channels and passages through the maze of reefs in 1802 and reported on the Barrier Reefs in volume 2 of his Voyage to Terra Australis.. Successive hydrographic expeditions continued the process through the 19th century. The Great Barrier Reef Expedition of 1928–29 contributed significant knowledge about coral physiology and ecology. Townsville's Australian Institute of Marine Science and a laboratory on Heron Island continue scientific investigation of matters relating to the reef and its ecology.
With over 1500 fish species, 400 species of coral and an attractive climate, the Barrier Reef has been a major tourist attraction since the 1890s, when Green Island was a pleasure-cruise destination for visitors from Cairns. The island pioneered the use of glass-bottomed boats in the early postwar years and opened an underwater observatory in 1954.
