China's National Stadium (R), also known as the "Bird's Nest", and the National Aquatics Center, also known as the "Water Cube", are seen during Earth Hour in Beijing March 31, 2012. Homes, office towers and landmarks in cities around the world turned off their lights from 8:30 pm local time for one hour to raise awareness about climate change and the threat from rising greenhouse gas emissions. REUTERS/David Gray (CHINA - Tags: ENERGY ENVIRONMENT SOCIETY SPORT)
A general view shows the Badaling section of the Great Wall before Earth Hour on the outskirts of Beijing, March 31, 2012. Earth Hour, when everyone around the world is asked to turn off lights for an hour from 8.30 p.m. local time, is meant as a show of support for tougher action to confront climate change. REUTERS/Jason Lee (CHINA - Tags: ENVIRONMENT BUSINESS TRAVEL CITYSPACE)
A general view shows the Badaling section of the Great Wall during Earth Hour on the outskirts of Beijing, March 31, 2012. Earth Hour, when everyone around the world is asked to turn off lights for an hour from 8.30 p.m. local time, is meant as a show of support for tougher action to confront climate change. REUTERS/Jason Lee (CHINA - Tags: ENVIRONMENT BUSINESS TRAVEL CITYSPACE)