This combo of photos shows the Seoul N Tower before (left) and after (right) the lights were turned off for Earth Hour in Seoul, South Korea, on March 26, 2011. Global landmarks around the world went dark on March 26 as "Earth Hour" took place with millions of people around the world switching off their lights. #

Lights are put out on the Sydney Harbour Bridge and the Sydney Opera House, at bottom left, in participation of Earth Hour in Sydney, Australia, on March 26, 2011.   [click image to view transition - javascript required]   #

Sheik Zayed Grand Mosque, Abu Dhabi, United Arab Emirates, on March 26, 2011.   [click image to view transition - javascript required]   #

The lights go out on the iconic face at Luna Park Sydney, Australia, on Saturday, March 26, 2011.   [click image to view transition - javascript required]   #

The skyscrapers of Singapore's central business district are pictured during Earth Hour on March 26, 2011.   [click image to view transition - javascript required]   #

Monumen Nasional in Jakarta, Indonesia, during Earth Hour, 2011   [click image to view transition - javascript required]   #

Piccadilly Circus lights go off in London, UK, during Earth Hour on March 26th, 2011.   [click image to view transition - javascript required]   #

The National Stadium (top), also known as the "Bird's Nest", and the National Aquatics Center, also known as the "Water Cube", can be seen during Earth Hour in Beijing, China, on March 26, 2011.   [click image to view transition - javascript required]   #

The Empire State Building is seen during Earth Hour in New York City on March 26, 2011.   [click image to view transition - javascript required]   #

Victoria Harbour panorama in Hong Kong on March 26th, 2011.   [click image to view transition - javascript required]   #

This combination picture shows the lights around Budapest downtown with the oldest Hungarian bridge "The Chain Bridge" and Buda Palace on March 26, 2011.   [click image to view transition - javascript required]   #

The Cathedral in Lausanne during Earth Hour on March 26, 2011.   [click image to view transition - javascript required]   #

The Lions Gate Bridge during Earth Hour in West Vancouver, British Columbia, on March 26, 2011.   [click image to view transition - javascript required]   #

The Petronas Twin Towers in Kuala Lumpur, when lights were turned off for Earth Hour March 26, 2011.   [click image to view transition - javascript required]   #

The hill of the Acropolis and the Herodion theatre during Earth Hour in Athens, Greece, on March 26, 2011.   [click image to view transition - javascript required]   #

Gotaplatsen Square and Kungsportsavenyn street during Earth Hour in Gothenburg, Sweden, on March 26, 2011.   [click image to view transition - javascript required]   #

The Peace Bridge in Tbilisi, Georgia, on march 26th, 2011.   [click image to view transition - javascript required]   #

The Sagrada Familia church designed by architect Antoni Gaudii during the worldwide Earth Hour, in Barcelona, Spain, on Saturday, March 26, 2011.   [click image to view transition - javascript required]   #

A view of the Las Vegas Strip during Earth Hour 2011 from the House of Blues Foundation Room inside the Mandalay Bay Resort & Casino on March 26, 2011 in Las Vegas, Nevada.   [click image to view transition - javascript required]   #

Scotland's Edinburgh Castle before and after the lights were switched off on March 26th, 2011.   [click image to view transition - javascript required]   #

The Belarusian National Library during Earth Hour in Minsk, Belarus, on Saturday, March 26, 2011. The monument of Belarusian enlightener Frantsysk Skorina is on the left.   [click image to view transition - javascript required]   #

Commercial buildings at Hong Kong's central district switch off nonessential lights on March 26, 2011 to mark Earth Hour.   [click image to view transition - javascript required]   #

The Brandenburg Gate during Earth Hour in Berlin on Saturday, March 26, 2011.   [click image to view transition - javascript required]   #

Aldar Headquarters Earth Hour 2011 before and after in Abu Dhabi, UAE, on March 26, 2011.   [click image to view transition - javascript required]   #

The Sydney city skyline on March 23, 2011, during Earth Hour on March 26, 2011.   [click image to view transition - javascript required]   #