Sydney (AP): Australia will be one of the first countries in the world to turn off its lights for an hour tonight as part of a global campaign to raise awareness about climate change.

Sydney - with its iconic Opera House and Harbour Bridge - was among hundreds of cities and towns in more than 35 nations promising to go dark, organizers said.

"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 are unlikely to be cut, it is the symbolic darkening of monuments, businesses and individual homes they are most eagerly anticipating.

Cities in Fiji and New Zealand will be the first to cut lights as clocks strike 8 pm.

Two hours later, lights will go off at Australia's most famous landmarks and in thousands of shops, apartments and houses nationwide. Cities elsewhere across Asia, Europe and North America will follow.

One of the last major cities to participate with be San Francisco, California - home to the soon-to-be dimmed Golden Gate Bridge.

"Earth Hour is about everyone and every organization, from individuals to global companies, joining together to own a shared problem - climate change," Ridley said. "The real goal for me is the number of people who take part."