A Yemeni soldier, pictured through a vehicle's windscreen, which was damaged by a bullet, gestures out of the window, in Marib, Yemen October 15, 2015. Marib is a city that is heavily armed even by the standards of Yemen, where the ready availability of weapons helped start civil war and is now preventing anyone coming out on top. Yemenis often say there are three guns for every person, a boast that has become an urgent concern in a country where the United Nations says the humanitarian situation is "critical". (Photo by Angus McDowall/Reuters)

Jing Li (L) and her husband Ke Xu wear Tibetan traditional costumes as they pose for their wedding photos in front of Tibetan prayer flags at the Nianqing Tanggula mountain pass in the Tibet Autonomous Region, China November 18, 2015. Jing, 22, and her husband Ke Xu, 23, both from Shiyan in northwestern Hubei province live in Tibet for three year. The couple married last month. (Photo by Damir Sagolj/Reuters)

A participant blows on yellow powder held in her hand during a Holi Party before the Gay Pride Parade in Barcelona on July 9, 2016. (Photo by Lluis Gene/AFP Photo)

Locals sort through garbage at a roadside dump in New Delhi on January 10, 2017 The national capital has been reeling under tonnes of garbage after sanitation workers went on a strike demanding payment of pending salaries. (Photo by Chandan Khanna/AFP Photo)

A Vietnamese woman, wearing the traditional “ao dai” long dress, poses for photos along peach blossom flowers ahead of the Vietnamese “Tet” (Lunar New Year festival), in a field in Hanoi, Vietnam, February 2, 2016. (Photo by Reuters/Kham)

A plastinated body presented as a pole vaulter is exhibited at the Menschen Museum, Museum of Humans, in Berlin, August 29, 2016. The museum was caught up in a legal dispute with the district office of Berlin-Mitte for years before it was able to meet the requirements made by the court. (Photo by Sophia Kembowski/DPA Photo via Newscom)

Revellers take part in the the 70th Annual Columbus Day Parade in New York, October 13, 2014. (Photo by Eduardo Munoz/Reuters)

Paramilitary policemen carry tyres as they take part in a training session in Zhangye, Gansu Province, China, March 1, 2016. (Photo by Reuters/Stringer)