Great Barrier Reef
Described scientifically, the Great Barrier Reef is the largest system of corals and associated life forms on earth. Not one, but a maze of 2,900 reels and many islands, it stretches for 2,300 km (1,400 miles) along the northern Queensland coast. As a mature ecosystem which has evolved over hundreds of thousands of years, and one of the world's most precious natural treasures, the fragility of the Great Barrier Reef cannot be overestimated.
Individual reefs are composed of the accumulated skeletal remains of plants and animals, supporting a veneer of living plants and animals. An estimated 1,500 species of fish and more than 300 species of hard reef-building corals, 4,000 mollusc species, and 400 species of sponge have been identified.
The reef is a major feeding ground for large populations of the endangered dugong, a large herbivorous marine mammal. Humpback whales breed here, and endangered green and loggerhead turtles nest. Sharing this environment are numerous other animal groups, including anemones, crustaceans, and marine worms. Above the Reef, the tropical skies are alive with sea birds.
Although World Heritage-listed, the reef supports activities that include commercial fishing boats, scientific research, and tourism. The Great Barrier Reef Marine Authority controls these activities and recently banned new resorts from discharging anything but tertiary-treated sewage into the sea.
Visitors to the Great Barrier Reef can choose from about 20 island resorts, ranging from five star to backpacker, or a full accommodation range on the nearby mainland, from where they can take a day cruise to the reef. While Cairns is the main gateway to the reef, boats leave regularly from all mainland towns and cities. Some anchor near the reef for the day, and others moor at large, purpose-built platforms holding up to 400 people. Either way, the day is spent swimming and diving with some of the world's most colourful fish, amid valleys of living coral.
All resorts, cruise-boat operators, and reef platforms must be approved by the marine park authority and are continually monitored to ensure they are not damaging reef life. Cruise-boat operators now include educational talks and films as part of their reef tours, while some have scientific programs. On the (few) bad-weather days, tourists can visit the world's largest living coral reef aquarium in Townsville, the only public aquarium in the world where corals have spawned.
Location: Queensland coast
World Heritage Criteria: Natural (All Four)
Best Time to Go: Dry season (April to October)
Area: 35 million hectares (86 million acres)
Details mentioned in this article were accurate at the time of publication