In this photo taken Friday, September 4, 2015, tourists Sarah and John Scott from Worcester, England, take a step back as a male silverback mountain gorilla from the family of mountain gorillas named Amahoro, which means “peace” in the Rwandan language, unexpectedly steps out from the bush to cross their path in the dense forest on the slopes of Mount Bisoke volcano in Volcanoes National Park, northern Rwanda. Deep in Rwanda's steep-sloped forest, increasing numbers of tourists are heading to see the mountain gorillas, a subspecies whose total population is an estimated 900 and who also live in neighboring Uganda and Congo, fueling an industry seen as key to the welfare of the critically endangered species as well as Rwanda's economy. (Photo by Ben Curtis/AP Photo)

A devotee of the Chinese Jui Tui Shrine has his face pierced with metal rods during a street procession during the annual Vegetarian Festival in the southern Thai town of Phuket on October 19, 2015. During the festival, which begins on the first evening of the ninth lunar month and lasts nine days, religious devotees slash themselves with swords, pierce their cheeks with sharp objects and commit other painful acts to purify themselves, taking on the sins of the community. (Photo by Nicolas Asfouri/AFP Photo)

Revellers take part in the traditional “Weiberfastnacht” (Women's Carnival) celebration in Mainz, Germany, February 4, 2016. Germany is celebrating its traditional carnival with tight security after assaults on women during New Year's Eve celebrations across the country. (Photo by Kai Pfaffenbach/Reuters)

Supporters of incumbent President Mahamadou Issoufou attend a campaign rally in Niamey, Niger, February 18, 2016. Niger holds presidential and legislative elections on Sunday. (Photo by Joe Penney/Reuters)

Buddhist novice poses for a picture while monks gather to receive alms at Wat Phra Dhammakaya temple, in what organizers said was a meeting of over 100,000 monks, in Pathum Thani, outside Bangkok April 22, 2016. (Photo by Jorge Silva/Reuters)

Playboy Bunnies pose for a selfie at the premiere of “The Transporter Refueled” at Playboy Mansion in Los Angeles, California August 25, 2015. The movie opens in the U.S. on September 4. (Photo by Mario Anzuoni/Reuters)

A man dressed as Father Frost, Russian equivalent of Santa Claus, sits by the fire with a reindeer Yakut, marking winter solstice at the Royev Ruchey Park of Flora and Fauna in the Siberian Taiga wood in the suburbs of Krasnoyarsk, Russia, December 21, 2016. (Photo by Ilya Naymushin/Reuters)

Players perform during a game at the first Bubble Soccer tournament in Hitzkirch, near Lucerne, Switzerland, June 27, 2015. Bubble Soccer, also known as Zorb Soccer, is becoming increasingly popular around the world. The game is a recreation of playing soccer whilst encased in an inflated zorb which covers the players upper-body and head. (Photo by Urs Flueeler/EPA)