The Bay Bridge and Golden Gate Bridge went dark tonight--but it was not because of an electrical problem.
It was part of the Earth Hour, a worldwide energy conservation movement.
The Golden Gate and Bay Bridge went dark from 8:30 p.m. to 9:30 p.m. Saturday night. The lights on the towers were powered down.
In Chicago, the host city of this year's Earth Hour, the city went all out and powered down lights in most of its downtown buildings.
Earth Hour first started in Australia in 2007, and now, more than 7,000 cities participate in the annual conservation event.