Earth Hour 2013

Cities around the world dimmed their lights to mark Earth Hour from 8:30 p.m. to 9:30 p.m. on Saturday, March 23.

2013 Earth Hour In Beijing

BEIJING, CHINA - MARCH 23: This composite photograph shows a huge LED sky screen before and during the Earth Hour 2013 power switch off at the Central Business District on March 23, 2013 in Beijing, China. Earth Hour, launched in 2007 in Australia by the World Wide Fund for Nature (WWF), a global conservation group, calls on people, organizations and cities to turn off their non-essential lights for one hour starting at 8:30 p.m. local time. (Photo by Feng Li/Getty Images)

Singapore Goes Dark For Earth Hour

SINGAPORE - MARCH 23: (EDITORS NOTE: Image is a digital composite.) The Arts and Science Museum and the Singapore city skyline is seen before (left) and after the lights were switched off to recognize Earth Hour on March 23, 2013 in Singapore, Singapore. Businesses and households around the world switch their lights off for an hour at 20:30 local time on March 23, to celebrate Earth Hour and raise awareness about climate change and renewable energy. Earth hour began in Australia in 2007 and is now celebrated in over 150 countries around the world. (Photo by Suhaimi Abdullah/Getty Images)