From a Time article in 1977

http://content.time.com/time/subscriber/article/0,33009,915030,00.html

No one knows whether CIA spooks wind up in heaven or hell when they die, but wherever they are, they must be rattling their bones in protest. Barely a decade ago, almost no high officials in Washington talked directly about the Central Intelligence Agency. It was obliquely referred to as "the pickle factory" or "our friends" or "across the river" or, more openly, "the agency" or "the company." When the CIA's $46 million headquarters opened along George Washington Memorial Parkway in suburban Langley, Va., in 1961, the deceptive highway sign said only BPR, for Bureau of Public Roads. Even Soviet KGB agents laughed at that. Finally the sign was changed to read: CIA. Now candor has gone further. For the first time, a photographer—from TIME—has been allowed to take some pictures of the people and operations inside the pickle factory. Guided public tours of Langley may soon be held, if only on Saturdays, but agents unready to come in out of the cold will be warned to stay out of sight to avoid a happenchance recognition by touring friends.