Photos: Cities dim for 'Earth Hour'
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Credit: AFP/Getty Images
This combo of pictures shows Octavio Frias de Oliveira bridge, over the Pinheiros river, with the lights on (L) and with the lights off (R) during the sixth annual Earth Hour on March 31, 2012 in Sao Paulo. 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 (Photo credit should read YASUYOSHI CHIBA/AFP/Getty Images)
