Throughout history, there have been many people who, for one reason or another, released classified information. Known as whistleblowers, they have alerted the public about other individuals, governments, or organizations who were secretly involved in illicit or unethical activities. From Frank Serpico to Edward Snowden, some call these individuals heroes, while others see them as traitors.
To learn more about the men and women who risked it all to share the truth, click through this gallery.