In this combination photo the China National Stadium, known as the Bird's Nest, with lights on (top) and off, is seen during the Earth Hour in Beijing on March 23,2013. Iconic landmarks and skylines were plunged into darkness on Saturday as the "Earth Hour" switch-off of lights around the world got under way to raise awareness of climate change. AFP PHOTO /WANG ZHAO (Photo credit should read WANG ZHAO/AFP/Getty Images)
