Around a billion people living in the world's major cities are being invited to turn off their lights at 8:30 pm local time on Saturday for "Earth Hour," described as the biggest mass campaign to demand action on climate change.
The Empire State Building, the Great Pyramids of Giza, the Petronas Towers in Kuala Lumpur, the Acropolis in Athens and the Taipei 101 skyscraper in Taiwan are among the buildings whose illuminations will be switched off for an hour, the organisers said.
More than 200 buildings in Paris will be dark for an hour, including the Louvre, Notre-Dame Cathedral and the Paris Opera House, according to the French branch of the World Wildlife Fund (WWF).
The Eiffel Tower will be plunged into darkness for five minutes and scrap a display of flashing lights scheduled for 9:00 pm, Paris city hall said.
Earth Hour was launched by WWF in 2007. Last year's event drew a claimed participation of 370 cities in 35 countries. Last week, the organisers said that 1,189 would be taking part this year.
People are being invited to provide blogs and short video clips on the ways of spending an hour in the dark. The campaign has been backed by the United Nations, whose secretary general, Ban Ki-moon, last week described it as a "a clear message... (for) action on climate change" in the runup to a crucial meeting in Copenhagen.
The December conference aims at crafting a new global pact on curbing emissions of greenhouse gases and providing help for poor countries bearing the brunt of climate change.