MEET THE REEF The Great Barrier Reef is the world's biggest coral reef system stretching for more than 2,300 kilometres along Australia's coast and covering an area the size of 70 million football fields If you set out to walk that same distance it would take you three weeks and that's without stopping to eat or take naps Along its great length are islands of gleaming white sand fringed in green mangrove forests and winding ribbons of reef
The Great Barrier Reef is also a World Heritage Site These precious sites around the world are chosen because they are amazing places that need to be treasured and protected
Of HOW THE REEF BEGAN A long time ago Australia was not the sort place where a reef could grow Stuck to Antarctica it was surrounded by a freezing sea far too cold for corals Then 85 million years ago when dinosaurs were still alive Australia split off and began to drift away towards the equator nearer to where it is today At this time in history the Earth was very cold Enormous ice sheets locked up masses of the ocean's water so sea levels were more than a hundred metres lower than they are now
Then as the last ice age ended around 10,000 years ago the world warmed up and the ice sheets melted causing an enormous flood As sea levels rose higher and higher great cliffs disappeared beneath the waves and hills were turned into islands Tiny young corals called larvae drifted in from other reefs and settled on this land that was suddenly underwater The sea became warm enough for corals to thrive and so the Great Barrier Reef began to grow As the seas rose higher some of the islands drowned completely but the corals kept growing upwards and outwards until they built wide flat reefs
