Members of the Bavarian police and the Bundeswehr, the German armed forces, guard a vehicle checkpoint as they demonstrate a dynamic operation as part of the GETEX anti-terror exercises during a media event on March 9, 2017 in Murnau, Germany. (Photo by Philipp Guelland/Getty Images)

An Iraqi military vehicle passes displaced Iraqi boys returning to their homes in West Mosul's Oreibi neighbourhood after government forces retook control of the area from the Islamic State (IS) group during the ongoing offensive against the jihadists on May 21, 2017. (Photo by Ahmad Al-Rubaye/AFP Photo)

A soldier from the South Korean army special forces breaks stone plates with her head during a martial arts demonstration for Memorial Day at Korea War Memorial Museum in Seoul, South Korea, Monday, June 6, 2016.(Photo by Ahn Young-joon/AP Photo)

Iraqi security forces vehicles take part in a military parade in the streets of Baghdad, Iraq July 12, 2016. Social media activists posted images of tanks, armored vehicles, cannons, soldiers, police officers, and PMF members in Saadoun Street. The photos spiked a rumor of military coup. Military and security advisor and expert Lt. Diyaa al-Wakil said that it is only normal for such rumors to spread since there were no prior announcements about the training. (Photo by Khalid al Mousily/Reuters)

A girl poses at an entrance of her house next to a bomb dropped by the U.S. Air Force planes during the Vietnam War, in the village of Ban Napia in Xieng Khouang province, Laos September 3, 2016. From 1964 to 1973, U.S. warplanes dropped more than 270 million cluster munitions on Laos, one-third of which did not explode, according to the Lao National Regulatory Authority. (Photo by Jorge Silva/Reuters)

Indonesian Air Force soldiers from the Paskhas corps shout slogans during a rehearsal for a ceremony marking the 70th anniversary of Indonesia's military in Cilegon, Banten province, October 3, 2015. Indonesia will celebrate the anniversay of its military on October 5. (Photo by Reuters/Beawiharta)

Al Fursan, the UAE Air Force aerobatic display team, perform during the opening of the Dubai Airshow in United Arab Emirates, Sunday, November 8, 2015. Dubai Airshow took off today to a slow start amid little expectations of major orders to match the multi-billion-dollar sales generated at the last edition of the biennial fair. (Photo by Kamran Jebreili/AP Photo)

Audrey Mata from Washington D.C in the U.S. dressed as Princess Leia, comes face to face with a replica of R2-D2 at the 'For The Love of The Force' Star Wars fan convention in Manchester, northern England, December 4, 2015. (Photo by Phil Noble/Reuters)