Review: World went dark for Earth Hour 2008

The Sears Tower is shown in the skyline of downtown Chicago shortly before the city participated in "Earth Hour" March 29, 2008. Thousands of lights that illuminate office buildings, public structures and monuments were switched off Saturday, darkening the city's skyline for one hour, in an effort to publicise the effects of climate change.

The Sears Tower is shown in the skyline of downtown Chicago shortly after the city participated in "Earth Hour" March 29, 2008.

A combo picture shows the Royal Castle in Stockholm, Sweden, moments before (top) and after the lights were switched off for Earth Hour, March 29, 2008. People switched off lights across the world on Saturday, dimming buildings, hotels, restaurants and bars to show concern at global warming. Up to 30 million people were expected to switch off their lights for 60 minutes by the time "Earth Hour" -- which started at 8 p.m. in Suva in Fiji and Christchurch in New Zealand -- completed its cycle westwards. More than 380 towns and cities and 3,500 businesses in 35 countries signed up for the campaign that is only in its second year after it began in 2007 in Sydney alone.

The Detroit skyline is shown during Earth Hour across the river from Windsor, Ontario March 29, 2008. Cities around the world switched off thousands of lights that illuminate office buildings, public structures and monuments for one hour Saturday evening, in an effort to publicize the effects of climate change.

Canada's CN Tower, normally aglow with light displays, is seen dark between office towers in Toronto, March 29, 2008. Non-essential lighting in government and office buildings as well as residences was turned off for one hour to publicize the effects of climate change.