North Korean leader Kim Jong Un smiles as he attends a flight training session by female fighter pilots Jo Kum Hyang and Rim Sol in this undated photo released by North Korea's Korean Central News Agency (KCNA) on June 22, 2015. (Photo by Reuters/KCNA/Antara Foto)

Winners celebrate after the annual Lelo match in the village of Shukhuti, Georgia, May 1, 2016. The villagers of Zemo (upper) Shukhuti and Kvemo (lower) Shukhuti have played the game every Easter Sunday for generations, with each side trying to carry the 16-kilogram ball to their end of the neighbouring villages. (Photo by David Mdzinarishvili/Reuters)

A protester uses molotov cocktails against riot police during May Day protests on May 1, 2010 in Athens, Greece. (Photo by Milos Bicanski /Getty Images)

A member of the “Ladies in White” dissident group shouts as she is carried away by police officers after they broke up a regular march of the group, detaining about 50 people, hours before U.S. President Barack Obama arrives for a historic visit, in Havana, Cuba March 20, 2016. (Photo by Ueslei Marcelino/Reuters)

Hot air balloons take to the skies as they participate in the mass assent at sunrise on the second day of the Bristol International Balloon Fiesta on August 11, 2017 in Bristol, England. More than 130 balloons have gathered for the four day event, now in its 39th year and now one of Europe's largest annual hot air balloon events, being hosted in the city that is seen by many as the home of modern ballooning. (Photo by Matt Cardy/Getty Images)

A general view shows the wreckage of armed trucks on the streets of Budapest at the time of the uprising against the Soviet-supported Hungarian communist regime in 1956. The picture was taken in the period between October 23 and November 4, 1956. (Photo by Laszlo Almasi/Reuters)

Performers wearing 19th century French military uniforms fire their weapons as they attack Allied forces during a reenactment of the Battle of the Nations, in a field in the village of Markkleeberg near Leipzig October 20, 2013. The east German city of Leipzig commemorated the 200th anniversary of the largest battle of the Napoleonic Wars on Sunday by reenacting the Battle of the Nations, with 6,000 military-historic association enthusiasts from all over Europe. The decisive encounter in which tens of thousands of soldiers were killed, took place from October 17-19, 1813, just outside of Leipzig. At the height of the hostilities Napoleon fielded more than 200,000 men against an Allied force of some 360,000 soldiers which included troops from Russia, Austria, Prussia and Sweden. (Photo by Fabrizio Bensch/Reuters)

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)