Great Barrier Reef, Australia
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The world's most famous and its largest (half the size of Texas), the Great Barrier Reef lines more than 1,400 miles of the Queensland coast, made up of more than 3,000 individual coral reef systems and hundreds of tropical islands. One of them is Green Island Reef Marine National Park, home to inland rainforests surrounded by white sandy beaches and magnificent coral reefs, many of them mere feet below the surface. Strap on a mask to take in the abundant marine life: 600 species of coral, sponges, mollusks, 133 types of sharks and rays, 30 kinds of whales and dolphins, dugongs, 1,625 species of tropical fish, sea horses, sea turtles, sea snakes, 120-year-old giant clams – the list goes on and on. Clearly you won't see a fraction of it, but do your best. Stay in Cairns and book day trips to Green Island with Cat Island Cruises, which is on the Great Barrier Reef Marine Park Authority's list of high standard tourism operations.