This link shows you photos of famous landmarks in a city turn off their lights during Earth Hour 2009. (Saturday, March 28, 2009 - 8.30 - 9.30 pm)
http://www.boston.com/bigpicture/2009/03/earth_hour_2009.html
http://www.boston.com/bigpicture/2009/03/earth_hour_2009.html