A couple embraces at the railway station in Kramatorsk, on May 20, 2023, amid the Russian invasion of Ukraine. (Photo by Sergey Shestak/AFP Photo)

Commander of the Joint Forces of the Armed Forces of Ukraine Serhiy Nayev holds puppies as he visits at positions near the border with Belarus, amid Russia's attack on Ukraine, in Zhytomyr region, Ukraine on September 20, 2023. (Photo by Gleb Garanich/Reuters)

Soldiers of Ukraine's National Guard 1st brigade Bureviy (Hurricane) fire a recoilless cannon during combat training at a military training ground in the north of Ukraine Friday, November 3, 2023. (Photo by Efrem Lukatsky/AP Photo)

A Ukrainian serviceman of 80th Separate Galician Air Assault Brigade makes a snow angel in a bomb crater, amid Russia's attack on Ukraine, at a position near Bakhmut in Donetsk region, Ukraine on January 25, 2024. (Photo by Inna Varenytsia/Reuters)

Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

A U.S. Army crew chief flying on board a CH-47F Chinook helicopter observes the successful test of flares during a training flight in Afghanistan, March 14, 2018. (Photo by Tech. Sgt. Gregory Brook/Reuters/U.S. Air Force)

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 Ukrainian serviceman walks an empty street in the front line city of Bakhmut, in Donetsk region, Ukraine on February 25, 2023. (Photo by Serhii Nuzhnenko/Radio Free Europe/Radio Liberty)