Earth Hour 2011

2009
Earth Hour 2009 was from 8:30 p.m. to 9:30 p.m. local time, March 28, 2009. 88 countries and 4,159 cities participated in Earth Hour 2009, ten times more cities than Earth Hour 2008 had (2008 saw 400 cities participate). One billion votes was the stated aim for Earth Hour 2009, in the context of the pivotal 2009 United Nations Climate Change Conference.
Among the participants in 2009 was, for the first time, the United Nations Headquarters in New York City. The U.N. conservatively estimates that its participation will save $102 in energy.