Many major city landmarks around the world are turning off their lights for one hour as they observe the "Earth Hour" campaign against climate change.
Australia's biggest city, Sydney, kicked off the event, cutting lights at 8.30 p.m. local time. Sydney Opera House switched colours to a low-intensity green to symbolize the need for the world to move to renewable energy.
Russia will turn off the lights on the Kremlin for the first time as part of the worldwide annual event.
The chief press secretary of the Kremlin Management Department, Viktor Khrekov, told ITAR-TASS that the backlights of the Kremlin Wall also will be extinguished and that only the star on the Kremlin's Spassky Tower will remain on.
Just outside the Kremlin walls on Red Square, the floodlighting of the onion-domed St Basil's Cathedral and the lighting on the GUM department store will be switched off.
Among other world-known architectural sites where backlights are to be turned off are Buckingham Palace and the House of Parliament in London, plus the Elysee Palace, the Eiffel Tower, the Louvre, and Notre Dame Cathedral in Paris.
The Empire State Building and the Statue of Liberty will go dark in New York. So will the Great Wall of China. And in Australia, the Sydney Opera House in Australia will switch colors to a low-intensity green to symbolize the need for the world to move to renewable energy sources.
Organizers expect hundreds of millions of people across the globe will also turn off their home lights for 60 minutes in a symbolic show of support for the planet.
The Earth Hour campaign started in Sydney in 2007 with an appeal to people and businesses to turn off their lights for an hour to raise awareness about carbon pollution, which is a major contributor to global warming.
Last year more than 150 countries and about 2 billion people participated in Earth Day.
Based on reporting by AFP and ITAR-TASS