Source: LAIST - Since 2007, one day a year has marked Earth Hour, during which folks across the globe shut off the lights and unplug for an hour to draw attention to energy overuse and climate change.
This year's event is now upon us: Earth Hour 2011 is tonight at 8:30 p.m. (local time).The event has grown since its origins, with 2009 and 2010 counting 88 countries and 128 countries, respectively, that took part. This year, the Empire State Building, the London Eye, the Eiffel Tower, and Victoria Falls, Zimbabwe will all go dark for Earth Hour, according to the event's website.