Photos: Cities dim for 'Earth Hour'
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Credit: AFP/Getty Images
Picture shows Brasilia's landmark, National Congress, with the lights off during the sixth annual Earth Hour on March 31, 2012. Millions of people were expected to switch off their lights for Earth Hour on March 31 in a global effort to raise awareness about climate change that was even to be monitored from space. AFP PHOTO/Pedro LADEIRA (Photo credit should read PEDRO LADEIRA/AFP/Getty Images)
