Earth Hour was started by WWF and partners as a symbolic lights-out event in Sydney in 2007. It’s now one of the world’s largest grassroots movements for the environment. “By switching off your lights on March 25 at 8:30pm, you will join millions of others in 190 countries in support of our planet.”
More information here to learn more about this event. See who is participating, what kind of impact it will make, and other ways to get involved.