2016 Rio Olympics, Swimming, Preliminary, Men's 100m Backstroke, Heats, Olympic Aquatics Stadium, Rio de Janeiro, Brazil on August 7 2016. Christopher Reid (RSA) of South Africa competes. (Photo by Dominic Ebenbichler/Reuters)

Pakistan girls make selfies holding a Pakistan-made weapon displayed at the four-day International Defence Exhibition and Seminar (IDEAS) 2016 in Karachi, Pakistan, Wednesday, November 23, 2016. (Photo by Shakil Adil/AP Photo)

Arisha, 9, takes instructions from coach Younus Qambrani during an exercise session at the first women's boxing coaching camp in Karachi, Pakistan February 19, 2016. For the past six months about a dozen girls, aged 8 to 17, have gone to the Pak Shine Boxing Club after school to practice their jabs, hooks and upper cuts. (Photo by Akhtar Soomro/Reuters)

A Russian-made rifle, carried by this woman when she was captured in Nearby Brush, is slung around her neck by South Vietnamese soldiers before they began their interrogation of her as Viet Cong suspect near AP La Ghi in Vietnam, August 25, 1965. The girl behind the woman, also was captured in the brush. (Photo by AP Photo)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

A member of the Revolutionary Armed Forces of Colombia (FARC) pose for a picture at a camp in the Colombian mountains on February 2005. (Photo by Frank Piasecki Poulsen)

A visitor looks at portraits of Mao Zedong amid his statues on display at a wholesale souvenir store in Shaoshan, Hunan Province in central China, 28 April 2016. Shaoshan is the hometown of former Communist leader Mao Zedong, popularly known as Chairman Mao. Thousands of visitors descend on this small Chinese town burrowed in the hills of Central China's Hunan province to pay homage to the “Great Helmsman” everyday. It is one of the core sites of the “Red Tourism” industry, where communist party cadres and ordinary Chinese tourists alike seek to relive the experiences and rekindle the spirit of the revolutionaries. (Photo by How Hwee Young/EPA)

A tank rolls out from a ship on a landing operation during military drills at the Black Sea coast, Crimea, Friday, September 9, 2016. Russia has deployed cruise missiles, multiple rocket launchers, tanks and its latest anti-aircraft system at massive military drills in Crimea. The drills which began across southern Russia and Crimea earlier this week and involve over 120,000 troops are some of the largest exercises Russia has held for years. (Photo by Pavel Golovkin/AP Photo)