The Las Vegas skyline, normally ablaze with light, goes dark each year in honor of Earth Hour.
The same eerie sight will happen again tonight, from 8:30 p.m. to 9:30 p.m. The Strip's casinos will power down their exterior lighting and marquees to raise awareness about climate change. Interior lights will remain on, though RM Seafood at Mandalay Bay and other strip businesses also plan to dim their lights to observe the occasion.
"Las Vegas is known for its bright lights and casinos, so it can draw even more attention" said Thomas Piechota, who oversees the Urban Sustainability Initiative at the University of Nevada, Las Vegas. UNLV also participates in Earth Hour.
Earth Hour is a worldwide initiative launched in 2007 by the World Wildlife Fund. Strip casinos, which have participated in the past, will this year join icons such as the Eiffel Tower, Buckingham Palace and Empire State Building in going dark for an hour. Libya will also take part in the event for the first time, with its national museum powering down.
Casinos owned by Caesars Entertainment, MGM Resorts, Wynn Resorts, Las Vegas Sands and Boyd Gaming are participating this year. The LVH and Trump International also are going dark.
Earth Hour draws many participants from the private sector, but few are as centralized as Las Vegas' resorts.
"The Strip is a collection of private companies and casinos, and the fact that so many of them have agreed collectively to participate is amazing," said Lou Leonard, head of climate change for the World Wildlife Fund. "To get so many private businesses to act together and make such a strong statement is pretty rare."
Gaming operators use Earth Hour to highlight their own sustainability initiatives, such as Caesars' company-wide CodeGreen program and MGM Resorts' commitment to energy savings, evidenced largely by CityCenter's Leadership in Energy and Environmental Design certifications.
Boyd Gaming three years ago launched a sustainability campaign to cut its electricity usage. Earth Hour is a symbol of the company's progress and commitment to going green, said Paula Eylar, Boyd's vice president of business and technology.
If casinos aren't careful, powering down the lights and turning them back on could actually flout Earth Hour's emphasis on reducing energy consumption.
"If everybody turns their lights back on at the same time, that has a negative effect," said Chris Brophy, MGM Resorts' vice president of sustainability. "We have done a very good job of timing our properties."
Turning off a casino's lights is a little more complex than flipping a switch, Brophy said, but with a little preparation and the powers of manual programming, the process is usually pretty smooth.
Consumers can get in on the action by turning off their own lights or by participating in the World Wildlife Fund's "I Will If You Will" challenge on YouTube. Users can post videos challenging others to achieve specific conservationist tasks.
Earth Hour itself doesn't do much to reduce energy usage, but that's not really the point, said Gwen Migita, Caesars Entertainment's director of sustainability and community engagement.
"It's symbolic of our commitment to address climate change," Migita said.