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 knight parades in the street during the traditional carnival parade in Cologne, western Germany, Monday, February 16, 2015. (Photo by Martin Meissner/AP Photo)

A design studio has launched its own dogs of war – by cleverly blending iconic Second World War planes with their canine counterparts. Photo: Wellington bomber with Golden Retreiver camoflage. A design studio has launched its own dogs of war – by cleverly blending iconic Second World War planes with their canine counterparts. (Photo by BNPS)

Nazi dictator Adolf Hitler greets supporters at a May Day gathering in the Olympic Stadium, Berlin. (Photo by Keystone). 1st May 1938

A bulldog named Munch, left, and a puppy named Dominique attend a news conference at the American Kennel Club in New York, Wednesday, January 30, 2013. The club announced their list of the most popular dog breeds in 2012 where the bulldog takes the fifth place spot from the Yorkshire terrier. (Photo by Seth Wenig/AP Photo)

Street fighting in Berlin between Government troops and Spartacists, during the Spartacist uprising which followed Germany's defeat in World War I. (Photo by Keystone/Getty Images). 1919

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)

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.)