Earth Hour 2012 was observed across the world on Saturday in a global effort to raise awareness about climate change and support for renewable energy.

People turned off their lights for an hour from 8:30 pm local time. Lights were also switched off in important landmarks including the Empire State building in US, the Big Ben in London, the Effiel Tower in Paris, the Sydney Opera House in Australia, the Petronas Twin Towers in Kuala Lumpur, the Great Wall of China and the Heritage museum in Serbia to observe earth hour.

According to the official Earth Hour website, Earth Hour 2012 took place in a record 150 countries and territories across 6,494 towns and cities.

In London, a human powered dance floor lit up the UK's flagship Earth Hour event at Somerset House. Street dance troupe Flawless, stars of Britain's Got Talent and new film StreetDance 2 counted down to switch off and performed a twilight routine.

In Russia, it was estimated that some 15 million people observed Earth Hour. The country, stretching across nine time zones, records the longest participation of any country in Earth Hour. In Dubai, More than 300 people gathered near the tallest tower Burj Khalifa in Dubai. They took part in the Earth Walk carrying candles and fluorescent lamps in their hands.

Several towns and cities across Euopean countries including Austria, Hungary, Romania, Bulgaria, Serbia, Croatia and Ukraine observed Earth Hour.

Take a look at the pictures of Earth Hour across the globe:

People light candles during Earth Hour after lights were turned off in Cali March 31, 2012. Lights started going off around the world on Saturday in a show of support for renewable energy.REUTERS
People launch floating paper lanterns into the sky in front of the Hermitage museum to mark Earth Hour in St. PetersburgReuters
The Bund on the banks of the Huangpu River is pictured during Earth Hour in ShanghaiREUTERS
The Petronas Twin Towers in Kuala Lumpur, a Malaysian landmark, are pictured during Earth HourReuters
A member of "Crispus" company performs during a show to mark Earth Hour in BucharestReuters
The Brooklyn Bridge is seen with its lights turned off in participation with Earth Hour in New YorkReuters
Children march while holding candles during Earth Hour in Lima. The banner reads, "Turn off your lights".Reuters
Chilean volunteers hold up candles during Earth Hour in Valparaiso city, about 121 km (75 miles) northwest of SantiagoReuters
Performers hold candles as they participate in Earth Hour celebrations after lights were turned off at the Opera House in HanoiReuters
The Palace of Culture is pictured after Earth Hour in WarsawReuters