Earth Hour: How World went dark for light

Emiratis light candles to mark Earth Hour near Burj Khalifa in Dubai. Earth Hour, when everyone around the world is asked to turn off the lights for an hour from 8.30pm local time, is meant as a show of support for tougher actions to combat climate change. (REUTERS)

People surround lit candles during the Earth Hour on March 26, 2013 in Cali, Valle del Cauca department, Colombia. Millions of people were expected to switch off their lights for Earth Hour in a global effort to raise awareness about climate change. Since it began in Sydney in 2007, Earth Hour has grown to become what environmental group WWF says is the world's largest demonstration of support for action on carbon pollution. (AFP)

Burj Khalifa before (L) and during Earth Hour in Dubai. (REUTERS)

The Empire State Buidling stands dark (Bottom) as its lights were turned off too mark "Earth Hour" in New York. (AFP)

The monument "As Bandeiras" before (top) and after lights were turned off during Earth Hour in Sao Paulo, Brazil. (AFP)

Large electronic billboards stand dark (R) on Times Square as their lights were turned off too mark "Earth Hour" in New York. (AFP)

The National Congress in Brasilia before (top) and during Earth Hour. (AFP)

The Serbian National Assembly building in Belgrade before and after submerging into darkness as part of the Earth Hour switch-off. (AFP)

The hostel ship Af Chapman (R) before and during Earth Hour in Stockholm, Sweden. (AFP)

Vienna's Rathaus (Townhall) before and after submerging into darkness as part of the Earth Hour switch-off in Vienna. (AFP)

The Eiffel Tower before and after submerging into darkness at 8:30 pm (local time) as part of the Earth Hour switch-off. (AFP)

The 'London Eye' and London skyline can be seen before (left) and after (right) the population of the city observed Earth Hour. (AP)

The Belarusian National Library taken before and after the lights are turned off  is seen during the worldwide Earth Hour. (AP)

The downtown Singapore skyline can be seen before (top) and after (below) the population of the city state observed Earth Hour. (AP)

The landmark India Gate is seen lit, top, and then the same location in darkness when the lights are turned out for one hour to mark Earth Hour. (AP)

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