New York City landmarks will go dark for an hour as part of a global "lights out" action for climate change.
The World Wildlife Fund says the many participants in Saturday night's event include Times Square billboards, and the Chrysler and Empire State buildings. Many Broadway marquee signs also will go off, as well as the decorative "necklaces" on East River bridges.
Residents also are urged to embrace the darkness. Earth Hour begins at 8:30 p.m. Saturday.
Lighting related to public safety will remain on.
The actor Ed Norton, who's a New York City resident, is the official ambassador for Earth Hour.