The S.O.E.
The Special Operations Executive was created by the British in 1940 with the intent and purpose to create spies for the Allied forces, using espionage and 'irregular warfare.' Nicknamed 'Churchill's Secret Army,' the S.O.E. became a formidable force during WWII. Why? Because they utilized an invaluable tool that could fly under the radar of the Axis powers...
...women.