Wed Nov 11, 2:21 AM ET

Cars cross a freeway during a blackout in Sao Paolo November 11, 2009. A major electricity outage at the Itaipu hydroelectric dam, the world's largest operational electricity generator on the border with Paraguay, left tens of millions of people in Brazil's two largest cities of Sao Paulo and Rio De Janeiro without power, according to the Brazilian director of the dam. REUTERS/Paulo Whitaker (BRAZIL ENERGY TRANSPORT)

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