March 26th, 2011

The World Wildlife Fund is hoping you'll turn out the lights for an hour this weekend in a show of support for the environment.

Millions are expected to turn off lights and appliances for an hour at 8:30 p.m. Saturday. This year marks the fifth annual Earth Hour organized by the fund.

The National Cathedral in Washington says it plans to participate again this year. The World Wildlife Fund says others pledging to participate this year include the city of Baltimore, where City Hall lights will be dimmed, as well at the National Aquarium.

Four thousand cities in more than 120 countries participated last year in the event that is backed by the United Nations as well as global corporations, nonprofit groups, schools, scientists and celebrities.