Sydney holds voluntary one hour blackout

March 31, 2007 Many lights in Sydney, Australia's largest city, were turned off for one hour at 19:30 local time (09:30 UTC) on March 31, 2007 to raise awareness of climate change. This Earth hour, which was organised by the World Wide Fund for Nature (WWF), received support from the government of New South Wales, many environmental groups and some businesses.

Many famous buildings such as the Opera House, Sydney Harbour Bridge and Luna Park took part.

Organisers also hoped the event would encourage Australians to conserve energy, claiming if various electronics were switched off when they were not in use the country's greenhouse gas emissions could reduce by up to 5%.