At 8:30 p.m. on March 27 (Saturday), Sydney¡¯s Opera House went dark. The Forbidden City went dark. The Las Vegas Strip went dark. Hundreds of millions of homes around the world went dark. They all turned off the light for Earth Hour 2010.

Climate change has been a big problem. People wanted to do something for the Earth. In 2007, people started Earth Hour in Sydney, Australia. Some 2.2 million homes and businesses turned their lights off for one hour.

¡±Climate change is a problem for each of us. Individuals, communities, businesses and governments around the globe have to do something,¡± said United Nations secretary-general Ban Ki-moon.

Earth Hour has now become a global movement. More than 50 million people across 35 countries joined the movement. Global landmarks, such as Sydney Harbor Bridge, The CN Tower in Toronto, The Golden Gate Bridge in San Francisco, and Rome¡¯s Colosseum, stood in darkness.