A US Marine leads two Viet Cong suspects in restraints during the Tet Offensive on February 20, 1967. (Photo by Bettmann Archive/Getty Images)

A woman walks in front of an art installation made of artificial fruits and vegetables during the “Moscow Autumn” festival in central Moscow, September 14, 2015. (Photo by Maxim Zmeyev/Reuters)

Residents cross a swelling dam, due to rising waters brought about by Typhoon Koppu, in Las Pinas city, metro Manila October 19, 2015. Powerful typhoon Koppu ploughed into the northeastern Philippines before dawn on Sunday destroying homes and displacing 10,000 people and whipping up coastal surges four meters (12 feet) high, disaster agency officials said. (Photo by Ezra Acayan/Reuters)

A picture made available on 20 October 2015 shows a foreign tourist posing for a souvenir photograph with a figure of a tiger head at a private zoo on Phuket Island, Thailand, 17 October 2015. Each day hundreds of tourists, including young children, visit the private tiger zoo where visitors are allowed to touch and pose for photographs with unchained tigers inside their enclosures. (Photo by Rungroj Yongrit/EPA)

Toyoda Gosei Co Ltd's personal mobility concept airbag car "Flesby" is displayed at the 44th Tokyo Motor Show in Tokyo, Japan, October 28, 2015. (Photo by Yuya Shino/Reuters)

Participants wearing historical attire compete on historical high wheel Penny Farthing bicycles in the traditional 'One Mile Race' at Letna Park in Prague, Czech Republic, November 7, 2015. The meeting of Penny Farthing bicycles is taking place for the 22th time. (Photo by Filip Singer/EPA)

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 young man, who says he is part of a local criminal gang, poses for a picture holding a gun in the neighbourhood of Korogcho in Nairobi, Kenya, March 19, 2015. Around 2 million people live in the shantytowns packed in around Kenya's capital. Crime is high amid chronic unemployment levels, while basic services and sanitation are scarce. Residents try to make the best of things, eking out a living and picking up work where they can. (Photo by Siegfried Modola/Reuters)