Several resorts along Las Vegas Boulevard turned the lights off Saturday night to mark Earth Hour.
Earth Hour is an annual tradition in which people switch off their lights to spread awareness about sustainability and climate change. Started by the World Wildlife Fund, it takes place this year on March 30, from 8:30 p.m. to 9:30 p.m. local time. (And it’s not to be confused with Earth Day, which is April 22.)
The symbolic effort started in 2007 in Sydney, Australia, when the WWF encouraged 2.2 million people to turn off their lights for one hour to support action on climate change.
Since then, millions of people around the world have taken part. Landmarks such as the Eiffel Tower, Big Ben, Sydney Opera House, the Empire State Building, Buckingham Palace, the Colosseum and Edinburgh Castle also have gone dark for an hour.