There is some interesting information about the D.C. tunnels and underground facilities in the discussion from the following video posted by SGT Report on December 13, 2016.

IT JUST GOES DEEPER AND DEEPER -- Richard Sauder

Video description: "Author Richard Sauder returns to SGT Report to discuss deep underground bases in around Washington DC, and across the country. We discuss many topics in this dynamic interview which is likely to become the seventh out of my last eleven videos to be deemed "not advertiser friendly" by big brother at You Tube."