Last year on Saturday 28 March at 8.30pm, nearly 1 billion people switched off their lights for an hour.
Organised by the international conservation charity WWF, Earth Hour is in its fourth year. In 2010, it is taking place on Saturday 27 March at 8.30pm.
So far, 579 cities and towns have signed up in 77 countries. The Las Vegas strip, the Grand Palace in Bangkok, the Empire State building, the Pyramids of Giza, the Acropolis, Tapei 101 tower in Taiwan and the London Eye are just some examples of important buildings that will be taking part.
Silva Tree switched off last year, and will be doing so again this year. We hope you join us in this important cause and help to alert our world leaders to the problems our planet faces. Copenhagen proved that it is up to us to act, so join us.
