Hong Kong's financial district's Bank of China Tower, Cheung Kong Centre, HSBC headquarters, Standard Chartered Bank and Legislative Council before during Earth Hour March 28, 2009. [click image to see it fade] (REUTERS/Bobby Yip) #
The Beijing Olympic swimming pool, better known as the "Water Cube" goes dark to observe the call to turn off non-essential lighting for one hour for climate change during World Wildlife Fund's Earth Hour in Beijing on March 28, 2009. [click image to see it fade] (STR/AFP/Getty Images) #
The skyline of downtown Toronto before and after Earth Hour on Saturday, March 28, 2009. [click image to see it fade] (AP Photo/THE CANADIAN PRESS - Darren Calabrese) #
The Sydney Opera House taken before and during Earth Hour in Sydney, Australia, on Saturday, March 28, 2009. [click image to see it fade] (Jack Atley/Bloomberg News) #
The Bund on the banks of the Huangpu River in Shanghai, China before and during Earth Hour on March 28, 2009. [click image to see it fade] (REUTERS/Aly Song) #
The Ericsson Globe Arena, seen during Earth Hour in Stockholm, Sweden March 28, 2009. [click image to see it fade] (REUTERS/Anders Wiklund/Scanpix Sweden) #
The Houses of Parliament in central London, moments before the lights are turned off to mark "Earth Hour", and as the lights are turned off, on March 28, 2009. [click image to see it fade] (Leon Neal/AFP/Getty Images) #
Lausanne's cathedral before and after its lights were switched off, on March 28, 2009 in Lausanne, Switzerland as part of the "Earth Hour" campaign. [click image to see it fade] (FABRICE COFFRINI/AFP/Getty Images) #
Lights are turned off at 8:30pm at Nokia Plaza at the LA Live entertainment complex in downtown Los Angeles, California on March 28, 2009 during a celebration to mark Earth Hour. [click image to see it fade] (ROBYN BECK/AFP/Getty Images) #
Photographs taken before and after the lights at the main roundabout at the main business district are turned off during Earth Hour in Jakarta, Indonesia, Saturday, March 28, 2009. [click image to see it fade] (AP Photo/Dita Alangkara) #
Lights on the Las Vegas Strip are viewed looking northbound from the Mandalay Bay Resort during "Earth Hour" in Las Vegas, Nevada March 28, 2009. [click image to see it fade] (REUTERS/Steve Marcus) #