LolliTop: Earth Hour 2012

A symbolic gesture to raise awareness about energy consumption, Earth Hour has grown since its beginning in 2007 in Sydney to now include observances in 147 countries and over 5000 cities. For one hour, lights are switched off at 8:30 local time on the last Saturday in March. Increasing public environmental awareness in China, which has overtaken the United States as the world's biggest polluter, has led 124 cities there to mark Earth Hour. Beginning with the second photograph, click the pictures to see them fade from lights on to the lights switched off during Earth Hour 2012.

Children light candles during a ceremony to mark Earth Hour in Islamabad, Pakistan on March 31, 2012. Earth Hour took place worldwide at 8.30 p.m. local times and as an annual global call to turn off lights for 60 minutes in a bid to highlight energy consumption. (Anjum Naveed/Associated Press)

The Marina Bay Sands hotel and ArtScience Museum (right) in Singapore on March 31, 2012. [ Click to fade ] (Matthew Lee/Reuters)

Commercial buildings in Hong Kong's Central district on March 31, 2012. [ Click to fade ] (Kin Cheung/Associated Press)

Malaysia's iconic Patronas Twin Towers in Kuala Lumpur on March 31, 2012. [ Click to fade ] (Saeed Khan/AFP/Getty Images)

Prambanan temple outside Yogyakarta city, Central Java, Indonesia on March 31, 2012. [ Click to fade ] (Dwi Oblo/Reuters)

The Great Wall at Badaling on March 31, 2012 in Beijing. About 124 Chinese cities joined the WWF worldwide initiative Earth Hour. [ Click to fade ] (Lintao Zhang/Getty Images)

The Sydney Harbour Bridge and city skyline on March 29, 2012 before Earth Hour, and during Earth Hour March 31, 2012. [ Click to fade ] (Tim Wimborne/Reuters)

City Hall (right) and the Cathedral of Our Dear Lady in Munich on March 31, 2012. [ Click to fade ] (Sven Hoppe/AFP/Getty Images)

St Stephen's Tower in London on March 31, 2012. [ Click to fade ] (Lewis Whyld/PA/Associated Press)

The Lions Gate Bridge in Vancouver on March 31, 2012. [ Click to fade ] (Darryl Dyck/The Canadian Press/Associated Press)

An ice-cream vendor works next to the India Gate in New Delhi on March 31, 2012. [ Click to fade ] (Parivartan Sharma/Reuters)

The Chillon Castle, Chateau de Chillon, in Veytaux, near Montreux and the Lake of Geneva, Switzerland on March 31, 2012. [ Click to fade ] (Jean-Christophe Bott/Keystone/Associated Press)

The Palace of Culture in Warsaw on March 31, 2012. [ Click to fade ] (Kacper Pempel/Reuters)

Serge Orru, General Director of French WWF branch, Isabelle Autissier, President of French WWF branch and Denis Baupin, Deputy Mayor of Paris work the lights of the Eiffel Tower during Earth Hour on March 31, 2012 in Paris. [ Click to fade ] (Antoine Antoniol/Getty Images)

The Brandenburg Gate in Berlin on March 31, 2012. [ Click to fade ] (Markus Schreiber/Associated Press)

St. Peter's Basilica in Rome on March 31, 2012. [ Click to fade ] (Filippo Monteforte/AFP/Getty Images)

An historical part of Tbilisi, Georgia on March 31, 2012. [ Click to fade ] (David Mdzinarishvili/Reuters)

A Soviet-era skyscraper on Kotelnicheskaya Embankment near the Moskva River in Moscow on March 31, 2012. [ Click to fade ] (Maxim Shemetov/Reuters)

The "Ham Ca Map" building in Hanoi on March 31, 2012. [ Click to fade ] (Kham/Reuters)

The Baiterek monument in Kazakhstan's capital Astana on March 31, 2012. [ Click to fade ] (Mukhtar Kholdorbekov/Reuters)

The Taipei 101 building in Taipei on March 31, 2012. [ Click to fade ] (Pichi Chuang/Reuters)

China's National Stadium (right), also known as the "Bird's Nest", and the National Aquatics Center, also known as the "Water Cube", in Beijing on March 31, 2012. [ Click to fade ] (David Gray/Reuters)