Earth Hour is a bright idea that will see London in darkness come 8.30pm on Saturday 27th March. The organisers, WWF want over a billion people to switch off their lights to support the fight against global warming.
London is making a huge gesture to be a part of earth hour by dimming the lights on iconic landmarks such as Piccadilly Circus, Canary Wharf, the Royal Albert Hall, the London Eye and the Gherkin.
So make sure you eat plenty of carrots at dinner time and to find out how you can join in click here.