People walk from Washington National Cathedral to the Islamic Center during the Faith Over Fear: Choosing Unity Over Extremism event in Washington. (Matt McClain/The Washington Post)

Washington National Cathedral, the city of Rockville and some businesses will shut off their lights Saturday night as part of the annual “Earth Hour” to highlight the need to address climate change.

The hour-long event is slated to start at 8:30 p.m. The Empire State Building, the Space Needle and the Las Vegas Strip are also planning to participate, according to the World Wildlife Fund, which helped organize the event.

The only light that will be on at Washington National Cathedral during that Saturday hour will be the blinking aircraft-warning light. Kevin Eckstrom, spokesman for the cathedral, said this is the fourth year it has participated.

“We want to mitigate the effects of climate change as much as we can,” Eckstrom said. “We believe that God created the Earth and pronounced it good, so our charge is to keep that creation in good shape and to leave that creation in as good of shape or better shape than we found it.”

Rockville, which has participated in the event since 2010, will be turning off nonessential lights at its Gude Maintenance Facility on Rothgeb Drive. The city also will be using Earth Hour to kick off a month of environmentally conscious programming, including local cleanups and an energy summit.

“By participating in this worldwide event, we recognize the need for climate change action and demonstrate the positive impacts of collective community action,” Erica Shingara, Rockville’s sustainability coordinator, wrote in an email.

The World Wildlife Fund is also asking musicians to broadcast live sets on Facebook Live with the hashtag #EarthHourLive.

“There’s never been a more critical moment for the world to show solidarity for and a strong commitment to fighting climate change,” the World Wildlife Fund wrote on its website. “By going dark, local government, cities, companies, landmarks and individuals send the message that we will remain steadfast as we deliver on the goals of the Paris climate agreement.”