Every year in March, people the world over recognize Earth Hour, a global initiative organized by the World Wildlife Fund, which encourages people to shut off their lights in order to save energy. Eco-friendly folks who join the movement tonight, March 25, 2017, from 8:30 to 9:30, now have a chance to win a trip to Iceland thanks to a global social media contest from Hilton.

To enter, simply post a photo and caption on Facebook, Twitter or Instagram describing how you observed Earth Hour this year and tag your images with #EarthHour and #TravelWithPurpose.

"We're incredibly proud that the Earth Hour movement was conceived at the Hilton Sydney nearly 10 years ago," said Maxime Verstraete, vice president of corporate responsibility, Hilton. "Almost every year since, our Team Members have combined their passion for hospitality with fun, local activities supporting the movement. This year we're looking beyond our more than 4,900 properties and inviting the world to be part of another exceptional Hilton experience. We hope our Travel with Purpose Contest will inspire others to learn more about climate change and energy conservation."

The grand prize winner will receive a five-night stay at the Canopy by Hilton Reykjavik City Centre in Iceland. If the winner chooses to travel in winter they can celebrate the ultimate dark-hour activity, searching for the spectacular Northern Lights. But they can redeem their travel prize in summer when 24-hour daylight means more time for sightseeing.

In addition to the global contest, Hilton properties around the world are also celebrating Earth Hour through creative individual programs and campaigns. Some are simply switching off their lights and rooftop signage, while others are arranging candlelit dinners or music sessions sans electricity for guests.

Since 2015, Hilton and WWF have partnered on such sustainable efforts as a water conservation, food waste reduction, serving sustainable seafood and accelerated efforts in adopting renewable energies at Hilton properties around the world.

READ MORE: Is this the ultimate Iceland itinerary?

Hilton has also developed and implemented LightStay, an award-winning platform that measures corporate responsibility performance. Hilton, which was also the first hospitality company to work with the U.S. Department of Energy's Superior Energy Performance to certify commercial buildings, has been ranked as a Top Green Company in the U.S. by Newsweek.

Hilton’s #TravelwithPurposeContest is open now and runs through April 1. The winner will be announced on Earth Day, April 22. Entrants must follow Hilton News Room (@HiltonNewsRoom) on their preferred platform to be eligible to win.

For more information on Hilton's sustainability plan, visit cr.hiltonworldwide.com.

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