Demonstrators hold placards during a rally in New Orleans, Louisiana May 8, 2010 to demand the cleaning of coasts as oil leaking from the Deepwater Horizon wellhead continues to spread in the Gulf of Mexico. BP Plc engineers positioned a four-story metal chamber above a gushing, ruptured oil well on the seabed of the Gulf of Mexico on Saturday in an unprecedented effort to contain a possibly catastrophic spill. REUTERS/Carlos Barria (UNITED STATES - Tags: DISASTER ENVIRONMENT CIVIL UNREST)