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

Israeli soldiers get ready to launch the Skylark drone during a drill on January 16, 2012 near Bat Shlomo, Israel. (Photo by Uriel Sinai/Getty Images)

A South Sudanese People Liberation Army (SPLA) soldier patrols the streets in Malakal on January 21, 2014. (Photo by Harrison Ngethi/AFP Photo)

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)

Soldiers try to attach the balloon to their car, June 1944. (Photo by Jared Enos/Mediadrumworld.com)

A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)

A seagull looks on as the Italian three-color special air force acrobatic team “Frecce Tricolori” flies over Rome and the Vatican Wednesday, June 2, 2021, as Italy celebrates the anniversary of its unification. (Photo by Andrew Medichini/AP Photo)

A man takes a picture of the mural painted by the street artist Harry Greb depicting the Italian music composer Ennio Morricone, a day after the 91-year-old composer's death, on July 7, 2020 in Rome, Italy. (Photo by Antonio Masiello/Getty Images)