On Saturday March 29th at 8:30pm, millions of people across the world are switching off lights for one hour - to celebrate their commitment to the planet. This is definition of the Earth Hour, the biggest event against climate change in history launched in 2007 and organized by WWF. In a few hours the world will be darker but millions of people will be happy to fight against a phenomenon that is starting to change our daily lives. Bacteria that are coming from the melting of the ices, high pollution that kills seven millions people a year (for more details go to the news section). These aren't little changes, these are threats to our future, to the future of our planet.

Earth Hour might be just a symbolic gesture (a big one) but half a million trees will be planted in the world's first Earth Hour Forest in a fight against the 6000 hectares of deforestation. Hectares of sea are being protected, raising the level of protection of Argentina’s seas from 1% to more than 4%. Concrete facts, fighting a common enemy that everybody must fight. This year, WWF is launching Earth Hour Blue, a digital crowd funding and crowdsourcing platform that enables participants to help raise funds and take action on a range of environmental issues.

A small gesture, switch off a light, alone doesn’t have an impact so why should we do that? Because together millions of small gestures become the sign of a great change.

Now what can you do in the Earth Hour? Switch off lights for one hour is the essential start but you can do more.

1. First of all sign up to the WWF website to know everything about Earth Hour.

2. Spread the word. Involve friends and relatives in the celebration of our planet.

3. Follow the Earth Hour Live on streaming.

4. Have fun in the dark! Switch off the lights, not the fun.

So remember, tonight at 8:30pm, switch off the lights and celebrate our planet and at the same time fight for it!

To know more about Earth Hour go to www.earthhour.org and www.wwf.org