From 8:30 to 9:30pm, restaurants served diners by candlelight and lanterns. Lights on billboards and buildings in financial districts were turned off. Flickering candles dotted town plazas. Mayors shut down streetlights in main thoroughfares. Using as little electricity as possible, Earth Hour celebrations worldwide consisted of street parties, free concerts, hot air balloon festivals, outdoor seminars and film viewings. Crowds brought candles, flashlights, bongo drums and glow sticks to celebrate the call to take a stand against climate change.

World landmarks -- including Greece's Acropolis, the Eiffel Tower in Paris, the London Eye, Egypt's Pyramids of Giza, Canada's Niagara Falls, the Sydney Harbour, the Las Vegas Strip, New York City's Broadway theater signs, the Empire State Building, Capetown’s Table Mountain, the Christ the Redeemer statue in Brazil and Malaysia's Petronas Twin Towers, -- disappeared from the skyline as cities observed the worldwide effort to save energy for an hour.

China joined the campaign for the first time, with Beijing turning off the lights at its Bird's Nest Stadium and Water Cube, the most prominent venues for the Olympics. Shanghai also cut lights in all government buildings and other structures on its waterfront.

Thailand's prime minister, Abhisit Vejjajiva, pressed a button that switched off the lights on Khao San Road, famous to budget travelers in Bangkok, packed with bars and outdoor cafes.

Earth Hour draws awareness for energy conservation, as businesses and households participate in switching off lights for an hour to cut energy use and curb greenhouse gas emissions from fossil fuels.

It is the third annual Earth Hour event, but participation expanded this year to over 84 countries and 2,800 cities compared to the 35 countries and some 50 million people switching off their lights in 2008, and 2.2 million in 2007. That event was inspired by an idea executed in Thailand in 2005, which was then taken up and pioneered by World Wildlife Fund (WWF) Australia with the sponsorship of the Sydney Morning Herald newspaper.

WWF CEO Carter Roberts says, “Turning off the lights is just the beginning. We're asking everyone to also make commitments to reduce their energy use during the rest of the year and to ask their elected representatives to do the right thing because we need climate legislation now.”

Plunging the world into darkness for an hour is not the end-all and be-all of the world’s environmental problems. But this event shows how simple it is reduce the amount of electricity we use and maintain it on a daily basis.

Who switched off and who didn't for an hour on Earth Hour in Singapore?

A Videolog of what happened at Earth Hour in Singapore

What did you do? Add your Earth Hour photos to theasiamag.com’s photostream

Did your actions make a difference? Find out by sharing your Earth Hour-inspired videos with us.