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)

Protest posters are attached to the walls surrounding the “Occupy London” camp outside St. Paul's Cathedral on November 01, 2011 in London, England. The Dean of St. Pauls Cathedral The Very Reverend Graeme Knowles resigned yesterday over the church's handling of the anti-capitalist “Occupy London” demonstration, which continues to occupy the grounds outside the cathedral. (Photo by Dan Kitwood/Getty Images)

A U.S. Marine kneels beside a Multi-Utility Tactical Transport ( MUTT) during a patrol as part of Rim of the Pacific (RIMPAC) 2016 an exercise held at Camp Pendleton, California United States, July 13, 2016. (Photo by Mike Blake/Reuters)

Scores of internally displaced Muslims are at the heart of the humanitarian crisis in Central African Republic, where violence between Christians and Muslims has threatened to spiral into genocide. Photo: An internally displaced woman carries her child in a camp for internally displaced people (IDPs), located at Bangui International Airport, April 10, 2014. (Photo by Goran Tomasevic/Reuters)

Young migrants gesture during a day of solidarity organised by local organizations and resdients for asylum seekers at a makeshift camp outside the foreign office in Brussels, Belgium September 6, 2015. Over 150,000 people seeking to enter Europe have reached Hungary this year, most coming through the southern border with Serbia, and many apply for asylum but quickly try to leave for wealthier EU countries. (Photo by Yves Herman/Reuters)

Students of the General Yermolov Cadet School take part in combined military training with members of a local youth military patriotic club at a boot camp of the Russkiye Vityazi (Russian Knights) military patriotic club in the village of Sengileyevskoye outside Stavropol, Russia February 8, 2017. (Photo by Eduard Korniyenko/Reuters)

A soldier helps another with her ear protection at the Terningmoen Camp in Elverum, Norway on March 23, 2017. Soldiers demonstrate their skills and tactics during a contract drill as they train to become part of the world's first all-female special forces unit, the Jegertroppen or “hunter troops”. (Photo by Carolina Reid/NBC News)

Naga Sadhus or Hindu holy men, smeared with ash, drink tea inside their makeshift camps near the confluence of river Ganges and the Bay of Bengal, ahead of Makar Sankranti festival at Sagar Island, south of Kolkata January 13, 2015. Hindu monks and pilgrims are making their annual trip to Sagar Island for the one-day festival of “Makar Sankranti” on Wednesday. (Photo by Rupak De Chowdhuri/Reuters)