@frontlinefortherecord: "These buildings might only be four stories high, but they go down ten stories.” In the years after 9/11, the U.S. government developed a massive maze of clandestine government and private agencies aimed at fighting terrorism in new and secret ways. FRONTLINE documented how reporters mapped the geography of this “top secret America,” and how they identified subterranean facilities beneath what appeared to be ordinary office park buildings. From spaces like these, they found, the government — with the support of a growing network of contractors — launched drone strikes, gathered and spread secret information, and engaged in cyber-conflict. For the full story, watch the 2011 documentary “Top Secret America,” now streaming on our Youtube channel.