Heron Island, Great Barrier Reef © Heron Island

Snorkelling on the Great Barrier Reef © Hamilton Island

The wow factor: Another UNESCO World Heritage Site, the Great Barrier Reef stretches for 1,430 miles (2,300km) off Queensland’s coast and is the longest coral reef system in the world. The largest structure built by living creatures, it is the only living thing that can be seen from space. It is home to over 1,500 fish species, one-third of the world’s soft corals, over 400 types of hard coral, over 30 marine mammal species including the endangered dugong, and six of the world’s seven turtle species. www.gbrmpa.gov.au

Did you know? The Great Barrier Reef Marine Park is 133, 200 square miles (345,000 sq km) in size – larger than the UK and Ireland combined. The reef system actually comprises around 2,900 individual reefs.

Experience: A four-night package staying on Heron Island, a coral cay on the Great Barrier Reef, with Tailor Made Travel costs from £549, with return flights from £1,175. A 12-night stay with Black Tomato on exclusive Wilson Island, just off Heron Island and only accessible by helicopter, costs £4,599 with flights. Or stay on Hamilton Island, in the Whitsunday Islands, and spend a full day exploring the reef as part of a four-day Great Barrier Reef Adventure costing from £1,050, excluding flights. www.tailor-made.co.uk, www.blacktomato.com,  www.hamiltonisland.com.au

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