An armed man herds his cattle close to the village of Nimini in northern South Sudan, February 8, 2017. In the chaos of South Sudan's civil war, it took three years for Nyagonga Machul to find her lost children. Machul had traveled from her village to the capital when President Salva Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer, in 2013. (Photo by Siegfried Modola/Reuters)

A wolf looks into the camera at the 30 km (19 miles) exclusion zone around the Chernobyl nuclear reactor in the abandoned village of Orevichi, Belarus, March 2, 2016. What happens to the environment when humans disappear? Thirty years after the Chernobyl nuclear disaster, booming populations of wolf, elk and other wildlife in the vast contaminated zone in Belarus and Ukraine provide a clue. (Photo by Vasily Fedosenko/Reuters)

Students hold their weapons before the swearing in ceremony for the military students, in Bucharest, Romania, Wednesday, October 25, 2017. The Romanian Army is proudly celebrating their Army Day and marking 100-years since the landmark battle of Marasesti, a key World War I battle in 1917 when Romanian and Russian soldiers defeated German troops, halting a German offensive. (Photo by Vadim Ghirda/AP Photo)

In this Saturday, December 30, 2017, picture a girl wearing a bear fur costume takes part in an annual bear parade in Comanesti, Romania. It's a tradition that originated in pre-Christian times, when dancers wearing colored costumes or animal furs went from house to house in villages, singing and dancing to ward off evil. (Photo by Vadim Ghirda/AP Photo)

Anne Owen and Abigail Owen-Pontez strap into “Elee”, a car made of cutlery from American Airlines during the Everyones Art Car Parade May 14, 2005 in Houston, Texas. The silverware was purchased by Houston artist Mark Bradford when the airline had to convert to plasticware after the September 11, 2001 attacks on the World Trade Center and Pentagon. The parade includes around 280 cars and is part of Art Car Weekend along with a street festival, parade, carnival, ball and other events. (Photo by Dave Einsel/Getty Images)

Kanphitcha Sungsuk, 21, (C), lines up with young men to speak to officers during an army draft held at a school in Klong Toey, the dockside slum area in Bangkok, Thailand, April 6, 2017. Thailand is widely seen as a paradise for gay and transgender people, but many complain of being treated as second-class citizens and the obligation to respond to the draft can be a nightmare when they turn 21. (Photo by Athit Perawongmetha/Reuters)

This photo taken on March 29, 2017 shows a young woman offering shots of liquer at a dance bar in Walking Street in Pattaya. Two hours east of Bangkok, Pattaya' s bawdy reputation hails from the Vietnam War era when US GIs partied in their downtime. (Photo by Roberto Schmidt/AFP Photo)