We stumbled upon a DC Metro Map from 1983. This was before they had the green line, and DCA was just "national airport". Check it out! http://www.clotureclub.com/2013/04/the-dc-metro-map-from-1983/

via ClotureClub.com http://www.facebook.com/photo.php?fbid=10151584286374254&set=a.10150317682289254.386795.103137984253&type=1