Members of the Russian Red Army Choir perform at Water Front Theatre in Beirut September 13, 2014. (Photo by Jamal Saidi/Reuters)

Ten-year-old Macy Friday, front left, reacts as she looks back at her family after meeting Hillary Clinton, front right, as she campaigns for U.S. Sen. Mark Udall, D-Colo., back, during a stop in the newly-renovated Union Station in Denver on Monday, October 13, 2014. Clinton appeared at an event to raise money for Udall's current re-election campaign and then headed to Las Vegas for another appearance on Monday night. (Photo by David Zalubowski/AP Photo)

Dhruva Aliman does a back somersault as he dismounts from a slackline on the beach at Santa Monica, California on October 19, 2014. Slackline is a balance sport where a line of webbing is adjusted at different levels of tension between two anchor points and participants (called slackers) perform tricks and stunts including somersaults. (Photo by Mark Ralston/AFP Photo)

A woman offers prayers by a road as a rickshaw puller transports passengers in Kolkata October 28, 2014. (Photo by Rupak De Chowdhuri/Reuters)

A P-51 Mustang named “Charlotte's Chariot” from the Southern Heritage Air Foundation flies past a cloud of smoke and fire from a nearby battle reenactment during the Wings Over Houston Airshow in Houston, on Saturday, November 1, 2014. Battle reenactments are part of the yearly show held at Ellington Airport. (Photo by Kar Hlava/AP Photo/Bay Area Citizen)

A Yemeni soldier, pictured through a vehicle's windscreen, which was damaged by a bullet, gestures out of the window, in Marib, Yemen October 15, 2015. Marib is a city that is heavily armed even by the standards of Yemen, where the ready availability of weapons helped start civil war and is now preventing anyone coming out on top. Yemenis often say there are three guns for every person, a boast that has become an urgent concern in a country where the United Nations says the humanitarian situation is "critical". (Photo by Angus McDowall/Reuters)

An Indian Sikh Nihang (a traditional Sikh religious warrior) Baba 'Avtar' Singh wears an oversized giant traditional turban as he pay respects at the Golden temple in Amritsar on November 10, 2015 on the eve of the Indian festival of Diwali, the festival of lights. There will be no spectacular show of light and fireworks this Diwali at the Golden Temple as the Shiromani Gurdwara Parbandhak Committee (SGPC) has decided not to celebrate the festival in the wake of series of incidents of alleged desecration of the Guru Granth Sahib (Sikh holy book). (Photo by Narinder Nanu/AFP Photo)

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)