Hour of Darkness for Energy Enlightenment

Parts of the Washington region joined 4,000 cities around the world -- dramatically up from 400 last year -- in a global call for energy conservation by darkening key buildings for an hour last night.

Nonessential lights were reportedly dimmed at Washington National Cathedral (which will keep them that way into today), the Walter E. Washington Convention Center and government buildings in the District and in Prince George's, Montgomery, Fairfax and Arlington counties. The embassies of Canada, Finland and Great Britain also participated in Earth Hour, sponsored by the World Wildlife Fund.

Eighty-four countries pitched in, including tourist icons such as the Eiffel Tower, the Sydney Opera House, Times Square, the Pyramids, Beijing's National Stadium and the Las Vegas Strip.

"This is a chance for people to make a statement and send a signal much in the same way the civil-rights movement sent a signal with the march on Selma and the speech Martin Luther King made on the steps of the Lincoln Memorial," said Carter Roberts, president of the D.C.-based World Wildlife Fund. "This is one of the biggest challenges facing us in the 21st century."

Said Samuel T. Lloyd III, dean of the National Cathedral, "As a community of faith, we recognize our planet as a sacred gift from God to enjoy, protect and ultimately pass on to the generations that follow."

This is the third consecutive year of the campaign against global warming and by far the largest in participation. The campaign started in 2007 in Sydney, the only city to participate.

It is unclear how much energy will be saved, Roberts said. But he hoped to get the attention of President Obama and Congress.

Staff writer Clarence Williams contributed to this report.