Started by WWF and partners as a symbolic lights-out event in Sydney in 2007, Earth Hour is now one of the world's largest grassroots movements for the environment, engaging millions of people in more than 180 countries and territories. It has become a catalyst for positive environmental impact, driving major legislative changes by harnessing the power of the people.
The Earth Hour is held every last Saturday of March between 8:30 and 9:30 PM. This year Earth Hour is on March 27th.
See more about the Earth Hour here.