DC is apparently riddled with secret fiber-optics carrying national security stuff — and it's maintained by a gang of Men In Black in black SUVs who will show up at a fiber break in minutes and send you and your backhoe to Gitmo if you're unlucky enough to break one of the unmarked conduits.
Within moments, three black sport-utility vehicles drove up, a half-dozen men in suits jumped out and one said, "You just hit our line."
Whose line, you may ask? The guys in suits didn't say, recalled Aaron Georgelas, whose company, the Georgelas Group, was developing the Greensboro Corporate Center on Spring Hill Road. But Georgelas assumed that he was dealing with the federal government and that the cable in question was "black" wire — a secure communications line used for some of the nation's most secretive intelligence-gathering operations…
Black wire is one of the looming perils of the massive construction that has come to Tysons, where miles and miles of secure lines are thought to serve such nearby agencies as the Office of the Director of National Intelligence, the National Counterterrorism Center and, a few miles away in McLean, the Central Intelligence Agency. After decades spent cutting through red tape to begin work on a Metrorail extension and the widening of the Capital Beltway, crews are now stirring up tons of dirt where the black lines are located.
Metro Dig at Tysons Stirs Underground Intrigue
(via Schneier)