Sydney's iconic Opera House and Harbour Bridge went dark Saturday night as the world's first major city turned off its lights for this year's Earth Hour, a global campaign to raise awareness of climate change.

The lights on the arch of Harbour Bridge were turned off at 8 p.m., followed shortly by the shells of the Opera House and other city landmarks. Most businesses and homes were already dark as Sydney residents embraced their second annual Earth Hour with candlelight dinners, beach bonfires and even a green-powered outdoor movie.

The city was noticeably darker, though not completely blacked out. The business district was mostly dark; organizers said 250 of the 350 commercial buildings there had pledged to shut off their lights completely.

The number of participants was not immediately available but organizers were hoping to beat last year's debut, when 2.2 million people and more than 2,000 businesses shut off lights and appliances, resulting in a 10.2 percent reduction in carbon emissions during that hour.

The effect of last year's Earth Hour was infectious. This year, 26 major world cities and more than 300 other cities and towns have signed up for the event.

New Zealand and Fiji kicked off the event this year. In Christchurch, New Zealand, more than 100 businesses and thousands of homes were plunged into darkness, computers and televisions were switched off and dinners delayed for the hour from 8 to 9 p.m. Suva, Fiji, in the same time zone, also turned off its lights.

Auckland's Langham Hotel switched from electric lights to candles as it joined the effort to reduce the use of electricity, which when generated creates greenhouse gases that contribute to global warming.

After Australia, lights will go out in major Asian cities, including Manila and Bangkok before moving to Europe and North America as the clock ticks on. One of the last major cities to participate will be San Francisco — home to the soon-to-be dimmed Golden Gate Bridge.

"What's amazing is that it's transcending political boundaries and happening in places like China, Vietnam, Papua New Guinea," said Earth Hour executive director Andy Ridley. "It really seems to have resonated with anybody and everybody."

Organizers see the event as a way to encourage the world to conserve energy. While all lights in participating cities are unlikely to be cut, it is the symbolic darkening of monuments, businesses and individual homes they are most eagerly anticipating.

Even popular search engine Google put its support behind Earth Hour, with a completely black Web page and the words: "We've turned the lights out. Now it's your turn."

"It is a wake-up call," said Sydney Lord Mayor Clover Moore. "We need to really plan for our future. (Earth Hour) is something we can all do together. Going global is very empowering."


HERE

Sat Mar 29, 5:31 AM ET

Previous 9 of 270 Next

In this combo photo the Sydney Opera House is illuminated by lights, top, and then shown with the lights switched off on Saturday, March 29, 2008, in Sydney, Australia. Australia's largest city will kick off a global dimming when it turns off its lights Saturday night for one hour in an effort to combat climate change. Sydney is the first of more than 370 cities and towns in more than 35 countries from Fiji to Ireland to Canada to take part in Earth Hour, organizers said.

(AP Photo/Mark Baker)

Sat Mar 29, 5:19 AM ET

Previous 10 of 270 Next

This combo picture shows the Sydney Harbor Bridge and Sydney Opera House illuminated by lights top, then seen with the lights turned off Saturday, March 29, 2008, in Sydney, Australia. Australia's largest city will kick off a global dimming when it turns off its lights Saturday night for one hour in an effort to combat climate change. Sydney is the first of more than 370 cities and towns in more than 35 countries from Fiji to Ireland to Canada to take part in Earth Hour, organizers said.

(AP Photo/Mark Baker)