From Wikipedia: The Impossible Spy is a film based on the true story of an Israeli civilian spy, Eli Cohen, who was recruited into Israel's secret intelligence agency (the Mossad) in the 1960s to become a spy in Damascus. Prior to his capture in 1965, Cohen was about to be appointed the third-most powerful figure in Syria—the Deputy Minister of Defense. Cohen's memorization of Syria's individual gun placements along the Golan Heights enabled Israel to defeat Syria in the Six-Day War in 1967.
