On March 31st, 2007 at precisely 8pm, the citizens of Sydney, Australia turned off all of the lights at home and at work for one entire hour. The lights along Sydney's famed Opera House and Harbour Bridge were off, weddings were held by candlelight, and the energy consumption of the city was reduced by more than 10% for that hour. That is the equivalent of taking 48,000 cars off the road!

Inspired, folks at the World Wildlife Fund have turned this demonstration into a global event. The global initiative was announced at the Bali Climate Convention with twelve flagship cities participating and many more expected to join. Said Toronto's Mayor, David Miller of the event, "I believe where nations fail to lead, cities must lead."

Chicago, Tel Aviv, Copenhagen, Manilla, Melbourne and Suva, Fiji are among the cities pledging their support. Earth Hour will take place at 8pm on March 29th in most participating cities, but those who do not live in participating cities can still sign up to make a personal pledge. To participate or to get your own community involved, go to the earth hour or visit their page on facebook.