Pupils of the Dao ethnic tribe return home from school along a hillside path at Suoi Thau village in Hoang Su Phi district of Vietnam's northern province of Ha Giang, located at the border with China, September 18, 2015. (Photo by Reuters/Kham)

In this Tuesday, July 14, 2015, photo, Phoe Thaw, center, a member of the White New Blood lethwei fighters club, a Myanmar traditional martial-arts club which practices a rough form of kickboxing, stretches during a practice session in their gym on a street in Oakalarpa, north of Yangon, Myanmar. Three of the club's members competed this summer on a stage a world away from the street gym: a mixed-martial-arts “One Championship” event broadcast globally on cable television networks, where fighters could receive $1,000 for each fight, according to coach Myint Zaw who started the traditional fighters' club 15 years ago. (Photo by Gemunu Amarasinghe/AP Photo)

Li Guoqiang talks on his phone outside his house at Guangfuli neighbourhood, in Shanghai, China, April 1, 2016. Li, 38, is a deliveryman who rents a place at Guangfuli. In a corner of Shanghai, surrounded by a cement wall, lies one of the world's most valuable fields of debris and garbage. On paper, the Guangfuli neighbourhood is a real estate investor's dream: a plot in the middle of one of the world's most expensive and fast-rising property markets. But the reality is more like a developer's nightmare, thanks to hundreds of people living there who have refused to budge from their ramshackle homes for nearly 16 years as the local authority sought to clear the land for new construction. (Photo by Aly Song/Reuters)

Chinese women ride a bicycle together on a street September 10, 2014 in Beijing, China. (Photo by Kevin Frayer/Getty Images)

Ranger trainees and trainee dogs simulate an ambush against rhino poachers at the Paramount Group Anti-Poaching training and K9 (canine) academy on November 26, 2014 in Magaliesberg, South Africa. One of the largest of its kind in Africa, the Academy will address the ever increasing need for training of Conservation Officers in anti poaching activities, wildlife contraband detection, specialist K9 solutions and Ranger K9 handler training – all of which have proven success rates in combatting and apprehending poachers and their activities. (Photo by Gianluigi Guercia/AFP Photo)

A masked man in military fatigues brings a blindfolded Irma Krat, arrested and held by pro-Russian protestors before her meeting with journalists near of occupied police station in Slaviansk, Ukraine, 21 April 2014. Pro-Russian activists are demanding broader autonomy from Kiev and closer ties to Russia. Pro-Russian activists continued occupying government, police and other administrative buildings in eastern Ukrainian cities, in defiance of an ultimatum by the Ukrainian government to lay down their weapons. Russia, the United States, the European Union and Ukraine on 17 April had agreed on steps to de-escalate the crisis in Ukraine during talks in Geneva, Switzerland. (Photo by Roman Pilipey/EPA)

Employees of a food stand take pictures of Titan, a robot created by England Cyberstein Robots, performing at the Danilovsly market in downtown of Moscow, Russia, 12 May 2014. Titan visited to Moscow to attend “Bal Robotov”, an interactive exhibition of the most recent advances in robotics which will be opened on 15 May in Artplay Moscow exhibition center. Titan worked alongside superstars including Will.i.am, Rihanna, Will Smith and Jackie Chan. (Photo by Sergei Ilnitsky/EPA)

A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)