A Ukrainian gunner sits in his 2S1 Gvozdika (122-mm self-propelled howitzer) on the front line in Southern Ukraine on October 8, 2022, amid the Russian invasion of Ukraine. (Photo by Dimitar Dilkoff/AFP Photo)

A Ukrainian service member smokes near a frontline, amid Russia's attack on Ukraine, in Donetsk region, Ukraine on February 8, 2023. (Photo by Yevhenii Zavhorodnii/Reuters)

Military chaplain Yurii looks on in a trench after an Orthodox Easter service for Ukrainian servicemen at their position, as Russia's attack on Ukraine continues, in Kharkiv region, Ukraine on April 15, 2023. (Photo by Sofiia Gatilova/Reuters)

A Ukrainian servicewoman fires a 2S7 Pion self-propelled gun at a position, as Russia's attack on Ukraine continues, on a frontline in Kherson region, Ukraine on November 9, 2022. (Photo by Viacheslav Ratynskyi/Reuters)

A serviceman of the Carpathian Sich Battalion is seen at his position on a frontline, as Russia's attack on Ukraine continues, near the town of Lyman, Donetsk region, Ukraine on December 8, 2022. (Photo by Viacheslav Ratynskyi/Reuters)

A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)

A German special anti-tank gun is ready to fire during the army maneuvers in Silesia, Poland, on September 22, 1928. (Photo by AP Photo)

Harris & Ewing Inc. photographed people, events, and architecture, particularly in Washington, D.C., during the period 1905-1945. Photo: Tests of Curtiss Palne for Army, Single Control. Created by Harris & Ewing. Published in 1912.