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)

Military helicopters fly in formation above a billboard with a picture of China's late Chairman Mao Zedong during a training session for the upcoming parade marking the 70th anniversary of the end of World War Two, on the outskirts of Beijing, July 2, 2015. Troops from Russia and Mongolia will march together with Chinese forces in a parade in Beijing in September to commemorate the end of World War Two, the government and state media said on Thursday, confirming the first two foreign participants. (Photo by Jason Lee/Reuters)

Gold Medalist Kristof Milak of Hungary during the medals ceremony of the 200m Butterfly final on day five of the swimming competition of the Tokyo 2020 Olympic Games at Tokyo Aquatics Centre on July 28, 2021 in Tokyo, Japan. (Photo by Aleksandra Szmigiel/Reuters)

Robert Lewandowski of Poland in action against Cristian Romero (R) of Argentina during the FIFA World Cup Qatar 2022 Group C match between Poland and Argentina at Stadium 974 on November 30, 2022 in Doha, Qatar. (Photo by Amanda Perobelli/Reuters)

A child reacts as a family takes a break next to a cooling mist at the Sensoji temple as Japanese government issued heat stroke alerts in 39 of the country's 47 prefectures in Tokyo, Japan on July 22, 2024. (Photo by Issei Kato/Reuters)

Handout photo provided by ParalympicsGB of Piers Gilliver competing in the Individual Sabre A - Men event during day six of the Paris 2024 Summer Paralympic Games on Tuesday, September 3, 2024. (Photo by ParalympicsGB/PA Wire)

A hippopotamus is sprayed with water on a hot summer day at Anna National Zoological Park in Chennai, India on April 26, 2017. (Photo by Arun Sankar/AFP Photo)

A C-17 Globemaster III crew prepares an air refueling mission September 27, 2012, at Joint Base Charleston, S.C. (Photo by Airman 1st Class Matthew J. Bruch/U.S. Air Force photo)