11. The infamous and secretive Cambridge Spy Ring is one of the most studied and examined double agent organization that is known to date. They were single-handedly responsible for over thirty to fifty years of espionage and secret selling during the Cold War. Along with infiltration into the British government, Michael Straight also managed to infiltrate the U.S. government under Franklin Roosevelt. He not only sold MI5 and MI6’s information to the KGB, but also the CIA’s and Secret Services secrets. He and the other members of the Cambridge Five, as they became known as, were responsible for covert operations in Europe, Cuba, and the United States. Although they were successful for many years, the organization toppled when Straight gave them up in order to qualify for a position in the White House staff. Many of them had already been under investigation, but they were all uncovered after Straight’s testimony.