Power lines crossing in front of the Sydney Harbour bridge and city skyline Photograph: Tim Wimborne/Reuters
University students participate in a mini marathon during Earth Hour at the Great Wall of China north of Beijing Photograph: Vincent Thian/AP
The country's National Stadium, also known as the Bird's Nest, and the National Aquatics Center, also known as the Water Cube before and during Earth Hour Photograph: David Gray/Reuters
The Marina Bay Sands hotel and ArtScience Museum as seen during Earth Hour Photograph: Matthew Lee/Reuters
The Petronas Twin Towers turned off the lights to mark Earth Hour in Kuala Lumpur Photograph: Lai Seng Sin/AP
Students sing in front of an opera house before its lights are turned off in Hanoi Photograph: HOANG DINH NAM/AFP/Getty Images
Prambanan temple before and during Earth Hour outside Yogyakarta city, Central Java Photograph: DWI OBLO/REUTERS
People hold candles and solar powered lamps at a gathering to mark Earth Hour in Mumbai Photograph: PUNIT PARANJPE/AFP/Getty Images
The India Gate in New Delhi before and during Earth Hour Photograph: PARIVARTAN SHARMA/REUTERS
Participants light candles during a ceremony in Islamabad Photograph: Anjum Naveed/AP
People launch a Chinese paper wish lantern in Moscow Photograph: KIRILL KUDRYAVTSEV/AFP/Getty Images
The Acropolis in Athens with the lights on and off Photograph: LOUISA GOULIAMAKI/AFP/Getty Images
People posing for pictures in front of the leaning tower of Pisa and the cathedral on the Square of Miracles with the lights on and off Photograph: FABIO MUZZI/AFP/Getty Images
A volunteer lights one of 5000 blue and green candles in an eight-meter shape of the Earth in front of the Brandenburg Gate in Berlin Photograph: Adam Berry/Getty Images
Papier-mache pandas set up by members of the WWF are pictured in front of the Eiffel Tower in Paris Photograph: KENZO TRIBOUILLARD/AFP/Getty Images
The lights are turned off in the Houses of Parliament to mark Earth Hour in London Photograph: Dan Kitwood/Getty Images
