epa02095741 The Houses of Parliament in London becomes one of the many global landmarks to be plunged into darkness as millions of people around the world switch off lights for an hour to protest against climate change on 27 March 2010. Several countries around the World have signed up for Earth Hour, during which homes, offices and landmarks will turn off their lights briefly, to raise awareness about climate change and the threat from rising greenhouse gas emissions. EPA/GEOFF CADDICK