The Vietnam Slide Project was created by photo editor Kendra Rennick, who began collecting photo slides after a close friend lost her father, a Vietnam veteran. Her friend found a box of slides that her father had taken while in Vietnam and from there Rennick has continued to collect photographs that Vietnam veterans took during their tours of duty. Here: A photo taken from the collection of D.Thornton, who served in the First Air Cavalry division of the United States Army. (Photo by D.Thornton/The Vietnam Slide Project)

People dressed in the historic uniforms of the Imperial Russian army take part in a re-enactment of the 1812 Battle of Berezina, to mark the 204th anniversary of the battle, near the village of Bryli, Belarus, November 27, 2016. (Photo by Vasily Fedosenko/Reuters)

A member of the Pakistani Anti-Narcotic Force (ANF) takes a selfie beside a pile of burning drugs and liquor during a ceremony at the Kacha Ghari army firing range, on the outskirts of Peshawar on October 16, 2018, after the contraband was seized in raids across the province. (Photo by Abdul Majeed/AFP Photo)

Viking re-enactors representing the rival armies of the Vikings and Anglo-Saxons skirmish near Clifford’s Tower during the Jorvik Viking Festival on February 23, 2019 in York, England. The annual Jorvik Viking Festival held in York is recognised as the largest event of its kind in Europe. This year the festival remembers the role that the Viking women played during those turbulent times. (Photo by Christopher Thomond/The Guardian)

Mozambique army soldiers take a ride on a motorbike in the streets of Palma, Cabo Delgado, Mozambique, 12 April 2021. The violence unleashed more than three years ago in Cabo Delgado province escalated again about two weeks ago, when armed groups first attacked the town of Palma. (Photo by Joao Relvas/EPA/EFE)

Ukrainian army soldier Dasha, 22, checks her phone after a military sweep to search for possible remnants of Russian troops after their withdrawal from villages in the outskirts of Kyiv, Ukraine, Friday, April 1, 2022. (Photo by Rodrigo Abd/AP Photo)

A supporter of presidential candidate and former chairman of the NATO Military Committee and Czech Army General Petr Pavel hands out leaflets, ahead of a direct presidential election that will start on January 13, in Prague, Czech Republic on January 5, 2023. (Photo by David W. Cerny/Reuters)

Jack London was a prolific photographer in addition to his writing. Here: Salvation Army barracks in London during Sunday morning rush – men who had been given tickets during the night queuing for free breakfast, 1902. (Photo by Jack London/Courtesy of Contrasto)