A World War II era P-51 Mustang fighter plane stands in front of a modern 747-8 freighter and a 757 passenger jet at The Boeing Company's centennial celebration in Renton, Washington, U.S. July 15, 2016. (Photo by Alwyn Scott/Reuters)

A hot air balloon in the likeness of Yoda from Star Wars prepares for liftoff at the 21st Philippine International Hot Air Balloon Festival at the former Clark US Air Force base in Pampanga Province, Philippines on February 9, 2017. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

London Mayor Boris Johnson takes part in a tug of war with members of the armed services to launch the London Poppy Day, outside City Hall, in London, October 27, 2015. London Poppy Day is a street collection event to raise money for serving and retired members of the armed services and their families. (Photo by Stefan Wermuth/Reuters)

Mae Zelinsky, left, and Betty O'Beda test ammunition on a .30 caliber rifle at a Remington Arms plant on April 30, 1943. Many women took over jobs that were left vacant when men went overseas to fight in World War II. (Photo by AP Photo)

“North and South Korea staged dueling war games Monday as threatening rhetoric from the rivals rose to the highest level since North Korea rained artillery shells on a South Korean island in 2010”. – Associated Press. Photo: North Korean soldiers with weapons attend military training in an undisclosed location in this picture released by the North’s official KCNA news agency in Pyongyang March 11, 2013. South Korea and U.S. forces are conducting large-scale military drills until the end of April, while the North is also gearing up for a massive state-wide military exercise. North Korea has accused the U.S. of using the military drills in South Korea as a launch pad for a nuclear war and has threatened to scrap the armistice with Washington that ended the 1950-53 Korean War. (Photo by KCNA/Reuters)

Young Christian Lebanese women, who are members of Kataeb Phalangist party, show their skill in handling arms while they train in a village between Christian-controlled eastern port of Jounieh and the Christian village of Zahle in the west Lebanon on September 9, 1976. The Lebanese civil war erupted in April 1975. (Photo by Erich Stering/AFP Photo)

Russian policewomen dressed in Soviet Army styled uniforms take part in the Victory Day parade in Volgograd on May 9, 2018. Russia marks the 73 rd anniversary of the Soviet Union' s victory over Nazi Germany in World War Two. (Photo by Mladen Antonov/AFP Photo)

A Houthi follower with fake blood on his clothes lies on the ground to represent a victim as others perform a war dance during a ceremony marking the first anniversary of the Houthi movement's takeover of Yemen's capital Sanaa September 21, 2015. (Photo by Khaled Abdullah/Reuters)