Social Networks Spread Word of '09 Global Blackout for Climate Change Awareness

Earth Hour: Earth Hour began in Sydney in 2007, when 2.2 million homes and businesses switched off their lights for one hour. In 2008 the message had grown into a global sustainability movement, with 50 million people switching off their lights. Global landmarks such as the Golden Gate Bridge in San Francisco, Rome’s Colosseum, the Sydney Opera House and the Coca Cola billboard in Times Square all stood in darkness.