From Amman to Warsaw, the skylines of 74 cities in 62 countries will darken for one hour as individuals, businesses, government buildings, schools and major landmarks turn off non-essential lighting in what will be the largest climate event in history.

Chicago is one of the U.S. cities participating. Join the effort! Visit earthhourus.com for more information.

When: Saturday, March 28, 2009, 8:30pm
What: Turn our your lights in support of taking actions to combat climate change
Who: All of Chicago, plus other citizens across the globe
Why: Flip your switch to show your support of climate action