Droid BB-8 arrives at the world premiere of the film “Star Wars: The Force Awakens” in Hollywood, California, December 14, 2015. (Photo by Mario Anzuoni/Reuters)

A Russian trenchmortar crew run to take up a new firing position in the Stalingrad area during the Great Patriotic War. (Photo by Keystone/Getty Images). October 1942

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

A scene showing one of the first trench battles is prepared for the opening of the 3D Panorama exhibition “Memory talks. The road through war” in the former Sevcabel port in St. Petersburg, Russia, 16 September 2019. Various 3D dioramas – containing genuine wartime items such as aircraft, tanks and artillery in original size – allow visitors to walk through scenes from the beginning to the end of WWII without any museum barriers. The exhibition opens from 19 September 2019 to May 2020. (Photo by Anatoly Maltsev/EPA/EFE)

German field telegraph operators at work in Warsaw. (Photo by Hulton Archive/Getty Images). 1st October 1914

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

A dejected German Grenadier carrying a machine gun on his shoulder in front of a building on fire during the German retreat in Russia. (Photo by Keystone/Getty Images). 1944

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)