A competitor reacts as she emerges from the water during the Tough Guy event in Perton, central England, January 26, 2014. The annual Tough Guy race – “the toughest race in the world” – at Perton in Staffordshire. Tough Guy claims to be the world’s most demanding one-day survival ordeal. First staged in 1987, the Tough Guy Challenge has been widely described as one of the hardest races of it’s type with up to one-third of the starters failing to finish in a typical year. (Photo by Darren Staples/Reuters)

A man carrying a sailfish walks through Hamarweyne district in South Mogadishu on March 25, 2015. (Photo by Carl De Souza/AFP Photo)

“Kids of Sapa”. Four little beautiful Hmong girls from Lao Chai Village, near Sapa, Vietnam. (Photo and caption by Felipe Hanower/National Geographic Traveler Photo Contest)

Brazilian natives of the Pareci tribe play head football with a hand-made ball for a demonstration, during the first day of the International Games of Indigenous Peoples, in Cuiaba, state of Mato Grosso, on November 10, 2013. 1500 natives from 49 Brazilian ethnic groups and from another 17 countries are gathering in Cuiaba until November 16 to compete in some 30 athletic disciplines, many of their own. (Photo by Christophe Simon/AFP Photo)

A man dressed as a Santa Claus poses at the front of the Kollhoff Tower at Potsdamer Platz square in Berlin December 14, 2014. (Photo by Hannibal Hanschke/Reuters)

In this undated handout photo taken by mrwed54, a woman poses for a photo by a lake in the Siberian city of Novosibirsk, about 2,800 kilometers (1,750 miles) east of Moscow, Russia. Thousands of Novosibirsk residents, from scantily clad women to newlyweds have been instagramming selfies near the lake nicknamed the “Siberian Malvides” after the far-flung tropical islands in the Indian Ocean. This is in fact is a man-made dumb of coal from a nearby power station that provides for most of Novosibirsk’s energy needs. Environmentalists are warning people against coming into contact with the water. (Photo by mrwed54 via AP Photo)

Somali government soldiers hold their positions during gunfire after a suicide bomb attack outside Nasahablood hotel in Somalia's capital Mogadishu, June 25, 2016. Somalia's al Shabaab Islamist group launched a suicide bomb attack on a hotel in the center of Mogadishu on Saturday before fighters stormed inside, police and the militant group said. Police said at least 15 people had died, including guards at the site, civilians and militants. Others were wounded. (Photo by Feisal Omar/Reuters)

A protester reacts as police use water cannon during a demonstration to demand changes in the Chilean education system in Santiago, Chile June 25, 2015. (Photo by Ueslei Marcelino/Reuters)