On March 31, a record number of countries will be dimming their lights to mark Earth Hour, an annual event designed to raise awareness of climate change issues and environmental problems facing our planet.

Earth Hour, organized by environmental organization the WWF, encourages individuals, businesses and governments to turn out their lights for 60 minutes in a bid to raise awareness of climate change.

The event first began in Sydney, Australia, in 2007 and has since spread around the globe with many of the world's most famous monuments, such as the Eiffel Tower in Paris and the Sydney Opera House, being plunged into darkness.

On March 30 organizers confirmed that this year a record 147 countries will be taking part in Earth Hour 2012 on March 31, up from the 135 countries that took part in last year's event.

Following Earth Hour on March 31 events will be taking place around the world to mark the annual UN organized Earth Day on April 22. Around 175 countries take part in Earth Day and the event encourages people to pledge to commit an "act of green," as part of the Million Acts of Green campaign.

Earth Hour takes place on March 31 at 8:30pm local time; see http://www.earthhour.org for more information.