Known as "Deep Throat," Felt was the FBI informant who helped Washington Post reporters Bob Woodward and Carl Bernstein take down President Richard Nixon during the Watergate scandal in 1974. His identity was kept secret until 2005.
A former CIA employee and government contractor, Snowden leaked classified NSA information in 2013, exposing several global surveillance programs. After being charged with violating the Espionage Act, Snowden fled to Russia.
In 1971 Ellsberg, a former U.S. military analyst, leaked the Pentagon Papers, a secret study of the U.S. government’s rationale behind its decision to involve itself in Vietnam.
Born Bradley Manning, the U.S. Army private was convicted in 2013 after releasing nearly three-quarters of a million classified or sensitive documents to WikiLeaks. Manning, a transgender woman, was sentenced to 35 years in prison for the offense.
A former White House staff member, Tripp became a key figure in the Monica Lewinsky scandal that led to the impeachment of then-President Bill Clinton in 1999.
The founder of WikiLeaks, Assange is behind more than 1.2 million disclosures, including sensitive documents furnished by Chelsea Manning. After facing extradition to Sweden, he sought refuge at the Embassy of Ecuador in London in 2012 and was granted political asylum by Ecuador.
A New York City police officer, Serpico exposed police corruption in the late 1960s and early 1970s, which prompted a landmark investigation into the NYPD. His story was made into a movie in 1973, starring Al Pacino.
A chemical technician, Silkwood became famous for exposing corporate practices related to health and safety of workers in a nuclear facility. She died mysteriously in 1974. Her story was later made into a movie starring Meryl Steep.
A former tobacco executive, Wigand went on “60 Minutes” in 1996 and stated that Brown & Williamson had intentionally increased the amount of nicotine in its cigarettes. He was portrayed by Russell Crowe in the 1999 film “The Insider.”
In the 1990s, Whitacre worked with the Feds to expose price fixing in agriculture by his own company, ADM. He spent eight-and-a-half years in prison after it was discovered he embezzled money. His story was made into 2009’s “The Informant!” starring Matt Damon.