Three Chinese soldiers at the time of a civil war in China. (Photo by General Photographic Agency/Getty Images). 1922

A man dressed as the “Star Wars” character Darth Vader sits on a bench in central Lviv, Ukraine, November 24, 2016. (Photo by Gleb Garanich/Reuters)

Five hundred replicas of the Stormtrooper characters from "Star Wars" are placed on the steps at the Juyongguan section of the Great Wall of China during a promotional event for "Star Wars: The Force Awakens" film, on the outskirts of Beijing, China, October 20, 2015. (Photo by Jason Lee/Reuters)

Mil Mi-8 combat helicopter flies over Moscow, Russia on May 7, 2019 during the dress rehearsal of a Victory Day air show marking the 74th anniversary of the victory over Nazi Germany in the 1941-1945 Great Patriotic War, the Eastern Front of World War II. (Photo by Sergei Savostyanov/TASS)

A Thorneycroft motor van as used during World War I. (Photo by Topical Press Agency/Getty Images). August 1914

South Korean teenagers participate in a warfare exercise as part of the Special Warfare Command's training course at a military base on August 4, 2011 in Seoul, South Korea. About 1,000 civilian volunteers including middle and high school students participated in the special force's four-day training programme to develop their spiritual and physical strength. (Photo by Chung Sung-Jun/Getty Images)

A woman walk by South Korean police during a anti-terror exercise on March 9, 2012 in Seoul, South Korea. The drill is part of South Korea's preparation for the upcoming 2012 Seoul Nuclear Security Summit, scheduled for March 26 and 27. Some 50 world leaders, including U.S. President Barack Obama, are expected to attend the summit to discuss how to make the world safe without nuclear weapons. (Photo by Chung Sung-Jun/Getty Images)

North Korean soldiers participate in a mass military parade at Kim Il-Sung square in Pyongyang on October 10, 2015. North Korea was marking the 70th anniversary of its ruling Workers' Party. (Photo by Ed Jones/AFP Photo)