London policemen wear gas masks for a training drill, 1937. Bettmann Collection

Skulls found on the Killing Fields of Choeung Ek, By: Bruno Ideriha

West Germany, 1956 German World War II prisoner released by the Soviet Union is reunited with his daughter.  

The forward sentry, watching for the enemy. The battalions made their decisions based on his reports.
Photo: Alexander Natruskin/Reuters