Robert Capa, 1936. Spanish Republican militiaman at the moment of being shot during the Spanish Civil War. Contested authenticity.
From Wikipedia
The Falling Soldier is a black-and-white photograph by Robert Capa, claimed to have been taken on Saturday, September 5, 1936. It was said to depict the death of a Republican soldier from the Libertarian Youth (FIJL) during the Battle of Cerro Muriano of the Spanish Civil War. The soldier in the photograph was later claimed to be the anarchist militiaman Federico Borrell García.