World | global warming Cities Ready Protest Blackout World 'Earth Hour' aims to raise awareness about global warming By Jane Yager Posted Feb 20, 2008 10:21 AM CST Copied A tourist stands on a path leading toward the Sydney Opera House in Sydney, Australia, in this March 22, 2007 file photo. Sydney initiated the now-global Earth Hour event last year. (AP Photo/Paul Miller) (Associated Press) An hour of darkness will descend on cities from Australia to Denmark on March 29 as homes and business turn out the lights to raise awareness about global warming. The event began last year in Sydney, where 2.2 million people shut off the lights, AFP reports. Two dozen cities around the globe will join this year's "Earth Hour." Chicago, Atlanta, San Francisco, and Phoenix are the American cities on the Earth Hour roster. Other cities taking part include Tel Aviv, Bangkok, and Copenhagen. Along with the Sydney Opera House, icons like San Francisco's Golden Gate Bridge, Chicago's Sears Tower, and Toronto's CN Tower will plunge into darkness. Read These Next Updated list of free days at national parks is raising some eyebrows. Olivia Nuzzi, Vanity Fair to part. Radiation expert has interesting new theory on why plane plummeted. Harvard visiting professor leaves US after antisemitism allegation. Report an error