Earth Hour began in 2007 in an effort to be the "single, largest, symbolic mass participation event in the world. Born out of a hope that we could mobilize
people to take action on climate change, Earth Hour now inspires a global community of millions of people in 7,001 cities and towns across 152 countries and territories to switch lights off for an hour as a massive show of concern for the environment."
2013 Earth Hour will be March 23, 8:30pm.
You can participate as an individual or a corporation. To see how you can be involved, visit EarthHour.org