A look at how the environment initative was recognized
People hold candles as they gather outside the Galileo Galilei planetarium to observe Earth Hour in Buenos Aires, March 29.Marcos Brindicci/Reuters
Students and visitors hold torches as they observe Earth Hour outside Fleming College's Frost Campus for Environmental Studies in Lindsay, Ont.Fred Thornhill/Reuters
Candles placed by participants to create the number 60, representing the minutes in an hour, marking Earth Hour in La Paz, Bolivia.Juan Karita/The Associated Press
People hold candles as they watch a performance during Earth Hour in Sao Paulo.Paulo Whitaker/Reuters
Saudis gather in a park during celebrations to mark the worldwide Earth Hour in Riyadh, Saudi Arabia.Hasan Jamali/The Associated Press
The "Puente Nuevo" (New Bridge) is seen during Earth Hour in Ronda, near Malaga, Spain.Jon Nazca/Reuters
The UNESCO World Heritage Cologne Cathedral and the Hohenzollern railway bridge along the river Rhine are seen during Earth Hour.Ina Fassbender/Reuters
The Old Bridge is pictured during Earth Hour in Mostar.Dado Ruvic/Reuters
The lights are turned off at the Kremlin during the worldwide Earth Hour in Moscow.Denis Tyrin/The Associated Press
Times Square is pictured during Earth Hour in New York.Eduardo Munoz/Reuters