Alan Turing, known as the father of computer science, single handedly solved the unbreakable German Enigma code. Like most geniuses, he displayed odd behaviors. His colleagues noted that he had a strange habit of chaining his coffee mug to a radiator in his office as theft protection.
On June 17, 1972, burglars broke into the Democratic National Committee's headquarters in the Watergate Office Building leading to what would become the Watergate scandal, eventually leading to the resignation of President Richard Nixon.
Alger Hiss was a well respected lawyer and State Department employee when he was accused of being a Soviet Spy by Whittaker Chambers.
Tony Mendez was decorated for his on-the-scene management of the "Canadian Caper" during the Iran hostage crisis, in which he exfiltrated six American diplomats from Iran in January 1980. This story was adapted for the screen and became the Academy Award winning film ARGO.
VENONA was a top secret United States counter-terrorism program that intercepted and analyzed Soviet diplomatic communications during from 1940-1980.
Margaretha Zelle, better known by the stage name Mata Hari, was a Frisian exotic dancer and courtesan who was convicted of being a spy and executed under charges of espionage for Germany during World War I and consequently causing the deaths of at least 50,000 soldiers.