More than 80 countries will this year participate in the Earth Hour climate change campaign, that began in Australia in 2007 with just over two million people taking part.
More than 2,800 cities and towns across the globe have signed on to switch off - edging organisers even closer to their ambitious target of one billion participants.
Two years ago, the campaign began at Sydney's Opera House.
This year Egypt's Great Pyramids at Giza will be plunged into darkness alongside another 828 global landmarks, including New York's Empire State Building, the Petronas Towers in Kuala Lumpur, the Eiffel Tower in Paris and the famed Coca-Cola sign in London's Piccadilly Circus.
Earth Hour organisers say that by turning off the lights for one hour from 8.30pm local time on Saturday, people can send a powerful collective message on the importance of action on climate change.
World leaders are due to meet in the Danish capital of Copenhagen in December to design a new global strategy to fight global warming.
Scientists say a strong agreement must come out of that meeting if the world is to avoid the worst effects of global warming.
The Earth Hour gesture also serves as a reminder to people to think about the way they consume energy and to modify their daily habits to cut down on power consumption.
More than 70 public events have registered to be part of the campaign in Australia this year.
As well as sending a message on climate change, Swinburne University astronomer Michael Murphy said the event would return the full beauty of the night sky to Australians, at least for an hour.
"The night sky is one of the last great nature reserves, but most people in Australia can't see it because of the city lights," he said.
The event's also a good excuse to indulge in some good old-fashioned romance.
Candle-lit speed dating will be held in most capital cities, while a 700 candle message of "lights off" will be laid out on Sydney's Coogee Beach.
A list of Earth Hour activities in Australia can be found on the website of the conservation group WWF, which founded the event.
well i guess nw u all f a clearer pic of wat earth hr is rite... ok now as one of many people in this globe lets us 2gthr make a change and work 2gthr to save our beloved earth. lets preserve this earth for our future. lets make a difference. lets switch off d lights. lets start to save our earth.tomorrow
28.March2009
at8.30pm to 9.30pm
switch off ur LIGHTS
p/s: to robbers, kidnapers, and any criminals whoever planed to rob, kidnap or any means of criminal on dat hour plez plez plez postponed it or cancle it. lets 2ghtr saved earth... coz it will make a different
