Countless landmarks captured in photos around the world went dark on Saturday, March 31, 2012 as a part of the Earth Hour celebration to raise awareness in a global effort for climate change.
Each year, Earth Hour is held on the last Saturday in the month of March where for one hour, lights are switched off. Last year, 135 countries participated and grew to 147 this year, according to the World Wildlife Fund (WWF).
Earth Hour 2012 is a celebration of people power; the world's largest mass event in support of the planet, WWF official Dermot O'Gorman said in a statement.
Earth Hour began online in Sydney, Australia with the dimming of the Harbour Bridge and Opera Hose and since has spread around the world to the Tokyo Tower to the Sky Tower in Auckland in New Zealand. In Paris, France, over 230 monuments and landmarks went dark on Saturday including the Notre Dame Cathedral and the Arc de Triomphe. The Eiffel Tower, however, only went dark for five minutes due to security measures, according to the Mayor's office. In New York, the Empire State Building went dim as well as the National Cathedral in Washington.
View the slideshow to see photos of Earth Hour 2012.