Competitors take part in the Christmas Really Wild Mud Run on a 4.6 miles course across undulating farm land at Celtic Camping, St David's, Pembrokeshire, Wales, December 12, 2015. (Photo by Rebecca Naden/Reuters)

Yakelin Hernandez, 18, poses for a photograph near The Malecon where The Carnival was held, on August 14, 2015. Colorful costumes, dancing, parades and street parties on the Malecon in Havana, Cuba are all part of Havana Carnival 2015 which was held in August. (Photo by Sarah L. Voisin/The Washington Post)

Inmates stand next to food during a Christmas event at Sarita Colonia male prison in Callao, Peru, December 18, 2015. For the event, inmates prepared Christmas meals for a culinary competition and took part in dances and songs. (Photo by Mariana Bazo/Reuters)

Handguns turned in from the public as part of the “Gun Turn-in” event where a $100 gift card is given for every firearm and a $10 gift card for each BB-gun, air-gun, or replica firearm turned over to police at Universal Missionary Baptist Church in Chicago, Illinois, U.S. May 28, 2016. (Photo by Jim Young/Reuters)

A young Hindu priest crawls under a cow as part of worship rituals during Tihar festival in Kathmandu, Nepal, Sunday, October 30, 2016. Cows are considered sacred to Hindus and are worshipped during Tihar festival, one of the most important Hindu festivals dedicated to the Goddess of wealth Laxmi. (Photo by Niranjan Shrestha/AP Photo)

People take part in a Halloween street party at Lan Kwai Fong on October 31, 2016 in Hong Kong. Halloween, a contraction of All Hallows' Evening, falls on the day before All Saints' Day on November 1, a holiday when Christians remember their deceased loved ones. (Photo by Lam Yik Fei/Getty Images)

Members of the Oath Keepers and general public return fire during a simulated attack as they take part in a tactical training session in northern Idaho, U.S. October 1, 2016. In April 2015 Reuters photographer Jim Urquhart was assigned to cover the Oath Keepers during a tour of the Sugar Pine gold mine in Oregon after the group of former cops, military, firefighters and other first responders had risen to prominence during a standoff in Nevada over land rights. (Photo by Jim Urquhart/Reuters)

Russian marines attached to the anti- submarine ship Admiral Tributs show their skills during a demonstration at a park in Manila on January 5, 2017, as part of their five- day port- of- call activities in the country' s capital. (Photo by Ted Aljibe/AFP Photo)