Posted Thursday, March 24, 2011, at 2:58 PM
Are you ready for Earth Hour? The fifth annual global greenevent, hosted by the World Wildlife Fund, asks citizens around the world toshut off lights for one hour on Saturday, March 26, at 8:30 p.m.local time, to raise awareness about climate change.
Back in 2007, Sydney, Australia was the first city to darkenits skies. In the years since, hundreds of millions of people in more than 100countries have taken part. And famous attractions around the world, including theEiffel Tower, the Las Vegas Strip, and Beijing's Forbidden City, now go dark tosupport the cause.
This year, Twitter is getting into the act. Users can apply to WWF to have theirprofile picture blacked out for the hour.