Visitors to the Nightmare Fears Factory in Niagara Falls, Canada, are obliged to navigate their way round the supposedly haunted building in total darkness while live actors jump out of them. The Nightmare Fears Factory team have been using hidden cameras to take pictures of their guests' terrified reactions, which they've then posted on the company's Facebook page. And it turns out they're all pretty funny. (Photo by Nightmare Fears Factory)

“Sokolica”. Sokolica, Poland. (Photo and caption by Marcin Kęsek/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

“Say cheese”. Cheetahs jumped on the vehicle of tourists in Masai Mara national park, Kenya. (Photo and caption by Yanai Bonneh/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

“Cub”. In the colony of penguins in South Georgia. (Photo and caption by Ondrej Zaruba/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

“Alice in Waterland” is a beautiful series of photographs re-imagining the Lewis Carroll classic underwater. It’s a creation of photographer Elena Kalis, who lives on a small island in The Bahamas, surrounded, she says, “by pristine clear warm water. Underwater is where I spend a lot of time; snorkeling, diving, photographing. It is fascinating how the world changes down below: light, sound, gravity and proportions are different from what we are used to”. (Photo by Elena Kalis)

A police officer removes a reveler from standing on a post as they guard and clear the street of revelers dressed in holiday themed costumes during SantaCon in New York Saturday, December 12, 2015. As thousands of Santa-suited merrymakers prepare to hit the city's streets and bars, organizers of the annual pub crawl say they're taking more steps than ever to deter naughty behavior. (Photo by Andres Kudacki/AP Photo)

Renee LeGrand, of Foothill Ranch, Calif., takes a picture among wildflowers in bloom Monday, March 18, 2019, in Lake Elsinore, Calif. About 150,000 people flocked over the weekend to see this year's rain-fed flaming orange patches of poppies lighting up the hillsides near Lake Elsinore, a city of about 60,000 residents. The crowds became so bad Sunday that Lake Elsinore officials closed access to poppy-blanketed Walker Canyon. By Monday the #poppyshutdown announced by the city on Twitter was over and the road to the canyon was re-opened. (Photo by Gregory Bull/AP Photo)

Michael Fröhlich's Jowett Javelin rotting car in his forest sculpture park in Neandertal Germany, September 11, 2016. An eccentric artist has collected fifty vintage cars and left them to rot in a forest – and now they're worth over $1 million. Former racing driver Michael Fröhlich, from Dusseldorf, Germany, has purposely crashed the cars into trees, buried them in mud and parked them on cliff faces in his estate's garden in the middle of the German Neanderthal. His collections includes a Jaguar XK120 worth $170,000, a Porsche 356 racer and a Buick worth $17,000. (Photo by Christoph Hagen/Barcroft Images)