The more secretive of the U.S. security agencies, the National Security Agency is an outgrowth of the WW II signals intelligence services of both the Army and the Navy. These were the groups that intercepted enemy communications and attempted to decode them. The different branches of the military traditionally were reluctant to cooperate in cryptanalytics, but the war necessarily pushed them together. Their cooperation left much to be desired, however, and President Harry Truman was forced to intercede and create a new agency, dedicated to communications intelligence.

On this day, November 4, in 1952, after a Harry Truman revision of the National Security Council Intelligence Directive, the National Security Agency came into being, charged with monitoring and interpreting foreign communications.

What goes at the NSA headquarters at a suburb of Baltimore, Maryland, is known only to the NSA. They have their own highway — limited to NSA employees only — and several years ago reported they needed more electricity to power their equipment. Most everything else is classified, leading some to dub it “No Such Agency,” or “Never Say Anything.”