Mar 29 - Towns and cities around the world are turning out the lights for an hour to highlight the threat from climate change.
Sydney's picture-perfect harbour was the first to be plunged into darkness to observe Earth Hour, the greenhouse awareness initiative launched in the city in 2007.
More than 2.2 million Sydney-siders took part in the event which will be observed around the world at more than 370 locations.
Sonia Legg reports.
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