A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

A general view shows sculptures made of waste material titled “Trash People” by German Artist HA Schult (unseen), on April 2, 2014 in Ariel Sharon Park, in the suburbs of Tel Aviv. Hundreds of human-size figures constructed from 20 tons of recycled material, including iron, glass, computer parts, cans and more, will dominate the sky line of Tel-Aviv city and be placed in the park. (Photo by Jack Guez/AFP Photo)

A Bukusu youth stands covered in mud in preparation for a circumcision ritual in Kenya's western region of Bungoma August 9, 2014. Circumcision rituals, which take place in August, are celebrated amongst some Kenyan tribes as an annual rite of passage into adulthood. (Photo by Noor Khamis/Reuters)

A Palestinian youth jumps with a sword as he demonstrates his ninja-style skills for the photographer in front of the ruins of buildings, that were destroyed in 2014 war, in the northern Gaza Strip January 29, 2016. The youths, who have been receiving martial arts training at local clubs in Gaza for the past two years, decided to form a team to hold regular shows in the hope that the publicity generated will eventually lead to them being invited to participate in international contests. (Photo by Mohammed Salem/Reuters)

A girl carries on her head a pile of dried shrubs she gathered for cooking and heating, in Kabul, Afghanistan November 18, 2015. (Photo by Omar Sobhani/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 girl reacts as she receives polio vaccine drops during a house-to-house vaccination campaign in Yemen's capital Sanaa, November 10, 2015. (Photo by Khaled Abdullah/Reuters)

Islamic female students practice the ancient Thai art of “Krabi Krabong” taught as a sport at the Darunsat Wittaya school on August 16, 2011 in Saraburi, Thailand. (Photo by Paula Bronstein/Getty Images)