People look at a man, who residents said was killed by al Qaeda militants, hanging on a bridge in Yemen's southeastern city of Mukalla June 17, 2015. Al Qaeda militants in Yemen killed two alleged Saudi spies, residents said, accusing them of planting tracking devices which enabled the assassination of the group's leader in a suspected U.S. drone strike. (Photo by Reuters/Stringer)

A U.S. Army soldier with the 10th Special Forces Group and his military working dog jump off the ramp of a CH-47 Chinook helicopter from the 160th Special Operations Aviation Regiment during water training over the Gulf of Mexico as part of exercise Emerald Warrior 2011 on March 1, 2011. (Photo by Tech. Sgt. Manuel J. Martinez/U.S. Air Force)

This file photo provided on Sunday February 15, 2015 by the Syrian anti-government activist group Aleppo Media Center (AMC), which has been authenticated based on its contents and other AP reporting, shows Syrian rebels firing locally made shells against the Syrian government forces, in Aleppo, Syria. (Photo by AP Photo/Aleppo Media Center)

In this Monday, March 28, 2016 photo, trainer Catrina Bloomquist works with Nav, an 11-year-old rescued California sea lion, as part of a new exhibit opening at the Georgia Aquarium. The aquarium is in the midst of celebrating its tenth anniversary, and as part of the festivities, patrons will be introduced to the newest faces in Atlanta, a group of rescued California sea lions. (Photo by David Goldman/AP Photo)

A team of Irish dancers celebrate after winning the under 12's group kaylee World Irish Dance Championship on April 2, 2016 in Brighton, England. The 8th World and 11th European Irish Dance Championships sees over 1500 dancers from 26 countries, speaking over 20 languages, competing in a variety of contests at the Brighton Centre on the city's beachfront. The event is organised by the World Irish Dance Association and is billed as the “Irish Dance Spectacular”. (Photo by Chris Ratcliffe/Getty Images)

In this Friday, March 28, 2014 photo, singers of the Moranbong Band, Jong Su Hyang, foreground, and Pak Mi Kyong, left perform on their stage in Pyongyang, North Korea. Step aside, Sea of Blood Opera. North Korean leader Kim Jong Un's favorite guitar-slinging, miniskirt-sporting girl group, the Moranbong Band, is back. And these ladies know how to shimmy. (Photo by Jon Chol Jin/AP Photo)

Students receive a group punishment during a military-style close-order drill class at the Qide Education Center in Beijing February 19, 2014. The Qide Education Center is a military-style boot camp which offers treatment for internet addiction. As growing numbers of young people in China immerse themselves in the cyber world, spending hours playing games online, worried parents are increasingly turning to boot camps to crush addiction. Military-style boot camps, designed to wean young people off their addiction to the internet, number as many as 250 in China alone. (Photo by Kim Kyung-Hoon/Reuters)

Climbers “painted” the Matterhorn red this week to celebrate a special anniversary. A group of mountaineers left red beacons along the route of the famous climb, which is one of the highest mountains in the Alps, and as nightfall came the imposing mountain came alive with colour. The event was organised by clothing brand Mammut to celebrate the 150th anniversary of the first explorers to scale the mountain. (Photo by MSN UK/Mammut)