From the LA Times:
Near Washington, D.C., construction crews watch for mystery ‘black’ wire
A Metrorail extension risks hitting communications lines, including some used for top-secret government intelligence operations.
This part happens all the time: A construction crew putting up an office building in the heart of congested Tysons Corner in McLean, Va., hit a fiber-optic cable no one knew was there.
This part doesn’t: Within moments, three black SUVs drove up, half a dozen men in suits jumped out, and one said, “You just hit our line.”