The iconic Opera House and Harbour Bridge went dark Saturday night as Sydney became the world's first major city to turn off its lights for this year's Earth Hour, a global campaign to raise awareness about climate change.
Thousands of homes were dark for an hour in Christchurch, New Zealand. The famed Wat Arun Buddhist temple in Bangkok, Thailand switched off its lights.
• Click here to view photos.
The three major cities were among 23 worldwide, along with 300 smaller towns, taking part in Earth Hour — a campaign by environmental group WWF to highlight the need to conserve energy and fight global warming.
"This provides an extraordinary symbol and an indication that we can be part of the solution" to global warming, Australian Environment Minister Peter Garrett told Sky News television, standing across the harbor from the dark silhouette of the Opera House.
Garrett said government offices and national monuments around the country took part in Earth Hour.
"We're not only talking the talk, we're walking the walk," he said. "Whatever your view is about the magnitude of the problem ... we can save money by using energy wisely and efficiently, and that gives us the added bonus of reduced greenhouse gas emissions."
In Sydney, a lightning storm was the brightest part of Sydney's skyline when the lights were turned off at the city's landmarks. Most businesses and homes were already dark as residents embraced their second annual Earth Hour with candlelight dinners, beach bonfires and even a green-powered outdoor movie.
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.
"I'm putting my neck on the line but my hope is that we top 100 million people," Earth Hour Australia chief executive Greg Bourne said.
New Zealand and Fiji kicked off the event this year. In Christchurch, more than 100 businesses and thousands of homes were plunged into darkness.
Also in New Zealand, 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 are believed to contribute to global warming.
WWF Thailand said the lights out campaign in Bangkok saved 73.34 megawatts of electricity, which would have produced 45.8 tons of carbon dioxide.
In Manila, the grounds of the seaside Cultural Center of the Philippines went dark after four city mayors ceremonially switched off the lights. Shopping malls turned off street lamps around the metropolis.
After Asia, lights were expected to go out in major European and North American cites as the clock ticks on. One of the last to participate will be San Francisco, California — home to the soon-to-be dimmed Golden Gate Bridge.
Organizers see the event as a way to encourage the world to conserve energy.
"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."
Popular search engine Google lent its support to Earth Hour with a completely black page and the words: "We've turned the lights out. Now it's your turn."
"Earth Hour is a call to action," said Sydney's Lord Mayor Clover Moore. "People have now responded and it's time to introduce some significant long-term changes."