Dr. P.A. Smithe was sent by the American Red Cross as a doctor and surgeon to work at a hospital in Vienna. He sailed to Europe in December 1915 and returned home in August 1916, according to his daughter, who donated his images to the National World War I Museum. Photo: Turkish army, including cavalry, infantry and artillery. (Photo by Dr. P.A. Smithe/National World War I Museum, Kansas City, Mo.)

A Russian trenchmortar crew run to take up a new firing position in the Stalingrad area during the Great Patriotic War. (Photo by Keystone/Getty Images). October 1942

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

A scene showing one of the first trench battles is prepared for the opening of the 3D Panorama exhibition “Memory talks. The road through war” in the former Sevcabel port in St. Petersburg, Russia, 16 September 2019. Various 3D dioramas – containing genuine wartime items such as aircraft, tanks and artillery in original size – allow visitors to walk through scenes from the beginning to the end of WWII without any museum barriers. The exhibition opens from 19 September 2019 to May 2020. (Photo by Anatoly Maltsev/EPA/EFE)

German field telegraph operators at work in Warsaw. (Photo by Hulton Archive/Getty Images). 1st October 1914

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

This is the moment a dog who had his legs cut off as a punishment, is able to walk again thanks to prosthetic limbs, and being rescued by John and Gill Dalley, a couple who moved to Phuket, Thailand, from Leeds to set up the Soi Dog Foundation, August 1, 2016. (Photo by Caters News Agency)

A ship being used for the filming of World War Z sets sail from Falmouth Harbour on August 4, 2011 in Falmouth, United Kingdom. The Cornish coastal town is currently being used to film the zombie film that stars Brad Pitt. (Photo by Matt Cardy/Getty Images)