The U.S. National Security Agency has been making worldwide headlines for a while now. But back in the 1970s, precious few people had ever even heard of the NSA. And if they had, they'd no idea just how sprawling this secretive organization had become ... and how the NSA was spying on American citizens.
But in 1971, Perry Fellwock, who was an analyst at the NSA, exposed the public to an agency that had surreptitiously grown so large that its budget exceeded that of the Central Intelligence Agency. It was also conducting some iffy campaigns, such as one called ECHELON, which was a code name for a system that intercepted all sorts of electronic communications, from faxes to phone calls to e-mails and more.
Fellwock went public with this information, and it had a massive ripple effect. The end result was new legislation prohibiting the government from spying on its own people without probable cause. And Fellwock may never have said a word if it hadn't been for our next famous whistleblower.