Major cities and towns across the world are switching off the lights for one hour at 8 p.m. on Saturday to make a statement about the threat of global warming.

The project, called “Earth Hour,” already began in Sydney, Australia, at 8 p.m. local time, with lights going out on buildings such as the Opera House and Harbour Bridge.

The Earth Hour first started last year, as an initiative of the World Wildlife Federation.

Even though some critics said the movement would not make a big change for the planet, the event’s organizers insist that the project could make people more aware about the consequences of global warming and make them feel like they were working together as a team to save the environment.

WWF also hopes that the participants in the event will think of more ways to fight global warming. A small but significant action would be replacing the house’s light bulbs with compact fluorescents.

The event’s official website, www.earthhour.org informs that on March 31 2007, when Earth Hour started in Australia, over 2.2 million Sydney residents and over 2,100 businesses turned off the lights for one hour, resulting in a 10.2 percent energy reduction across the city.

This year, Earth Hour spread all around the globe and 24 important cities in the world are expected to participate in the action, including Dubai, Toronto, Dublin, Atlanta, Chicago, Copenhagen, Seoul, Rome and Mexico City.

"We're aware of villages in Norfolk in England that are doing Earth Hour and we're aware of the big cities like Chicago and Sydney that are doing it," Andy Ridley of the World Wildlife Fund told BBC.