An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

Boards stand lined up at the Rocinha Surf Association, ASR, headquarters at Rocinha slum in Rio de Janeiro, Brazil, Thursday, July 2, 2015. ASR has given free lessons to over 2,000 children from Rio's shantytowns in the hopes of keeping the boys, who are mostly in their early teens and a few girls occupied by the sport and off the streets. (Photo by Felipe Dana/AP Photo)

A wounded Syrian girl looks on at a make shift hospital in the rebel-held area of Douma, east of the capital Damascus, following shelling and air raids by Syrian government forces on August 22, 2015. At least 20 civilians and wounded or trapped 200 in Douma, a monitoring group said, just six days after regime air strikes killed more than 100 people and sparked international condemnation of one of the bloodiest government attacks in Syria's war. (Photo by Abd Doumany/AFP Photo)

In this Friday, February 27, 2015 photo, an Israeli high-school senior preparing to join the Israeli military later this year participates in a privately run training camp for military combat fitness near Yakum, central Israel. With a mandatory three-year military service looming after graduation, teenage boys, and increasingly girls too, are gearing up for the draft, getting into shape and trying to improve their chances of acceptance into elite combat units. (Photo by Oded Balilty/AP Photo)

Syrian refugee girl Nur El-Huda, 9, shows a drawing of her home in Syria, in her classroom in Yayladagi refugee camp in Hatay province near the Turkish-Syrian border, Turkey, December 16, 2015. Syria's conflict has left hundreds of thousands dead, pushed millions more into exile, and had a profound effect on children who lost their homes or got caught up in the bloodletting. The drawings of young refugees living in Turkey show their memories of home and hopes for its future. The pictures also point to the mental scars borne by 2.3 million Syrian refugees living in Turkey, more than half of them children. (Photo by Umit Bektas/Reuters)

In this photo taken on Sunday, February 15, 2015 a girl runs away from a “Mamuxarro” during the carnival, in the small town of Unanu, northern Spain. In the northern Spanish ancient village of Unamu, people dress up as “Mamuxarro”, folkloric figures in white with a red sash and a metal mask to cover their faces as they pursue townsfolk with sticks. According to custom, their “victims” (usually young women) must kneel and kiss the mamuxarro’s knee after he makes the sign of the cross on their forehead. (Photo by Alvaro Barrientos/AP Photo)

Girls take a selfie at the haze shrouded Batanghari River bridge in Jambi, Indonesia Sumatra island, September 14, 2015. Indonesian islands are blanketed in the so-called “haze”, caused by slash-and-burn clearances on the islands of Sumatra and Borneo, which makes thousands sick, delays flights and pushes air quality to unhealthy levels in neighboring Singapore and Malaysia. (Photo by Reuters/Beawiharta)

Nguyen Manh Quan (top), 26, a civil servant, carries a girl using his throat area as he performs during a showcase of the traditional Thien Mon Dao kung fu at Du Xa Thuong village, southeast of Hanoi, Vietnam May 10, 2015. Thien Mon Dao, a traditional Vietnamese martial art, was formed by 18th century villagers in Du Xa Thuong village, who believed the art form could help improve health as well as fight against foreign invaders. There are currently about 3,000 practitioners including farmers, industry workers and state servants. These practitioners say they are able to bend metal against their bodies and carry heavy objects using their throats, eyes or tongues, as well as run across the surface of a river, according to Thien Mon Dao kung fu master Nguyen Khac Phan. (Photo by Reuters/Kham)