Earth Hour is an initiative suggested by the World Wildlife Fund (WWF) to address global climate change, hoping that individuals, communities, businesses and governments turn off lights One hour in on the last Saturday 20:30-21:30 of March each year to show their support addressing on climate change. Now climate change caused by excessive carbon dioxide emissions greatly threats the survival of humanity on the planet. The public can reduce this threat impact on the world by changing the attitude of the people to the global carbon dioxide emissions. Earth Hour started in the world again on March 27, 2010 after 2009.

"Earth Hour" campaign first started in Sydney, Australia at 8:30 in the evening on March 31, 2007. At that night, more than 2.2 million Sydney households and businesses turn off lights and appliances for one hour. The electricity saved by lights turned off for one hour could support 20 million TV sets in 1 hour and 50,000 vehicles to run 1 hour according the statistics after the event. More people participated in this event reflected that the visible stars at that night were more times than usual.　　

Subsequently, the "Earth Hour" from the limited size beginning with surprising speed quickly swept the world. After only one year, "Earth Hour" has been recognized as the world's largest one of the actions to address climate change and become a global sustainable development activity. In March 29, 200850 million people in 35 countries participate in and prove the actions of individuals gather together can really change the world. 　　

In 2009 "Earth Hour" was launched formally in China. "Earth Hour" comes to Baoding "China Power Valley" in China which is the first city to join the activity announced by official. In addition, the China's mainland cities participated in this activity recognized officially by the WWF are Beijing, Shanghai, Dalian, Nanjing, Shunde, Hangzhou, Changsha, Changchun, Hong Kong, Macau and other cities. On 28 March 2009 from 20:30 to 21:30, the cities mentioned above turned off the lights for one hour. More than 80 countries and more than 3,000 cities and regions work together to created this beautiful "dark moment " to contribute for the future of the Earth.　　

All lights in National Football Museum in England, the world's tallest hotel tower, the CN Tower in Toronto, Federal Building in Moscow, and President of the Republic of Italy in Rome's Palace residence Kuilinale turned off for one hour. The landmark building in Victoria Pier in Hong Kong also turned light for an hour to express the determination to address climate change.

From: baidu.com