Lights go out in worldwide climate change campaign

From an Antarctic research base and the Great Pyramids of Egypt to the Empire State Building in New York and the Sears Tower in Chicago, illuminated patches of the globe went dark for Earth Hour, a campaign to highlight the threat of climate change.

Time zone by time zone, nearly 4,000 cities and towns in 88 countries joined the event sponsored by the World Wildlife Fund to dim nonessential lights from 8.30pm to 9.30pm. The campaign began in Australia in 2007 and last year grew to 400 cities worldwide.