I'm sure there are several "Thoroughfare Gaps" but that one looks like the one on 66 between Manassas and Front Royal. When I'm coming home from those times I've had to go to Northern Virginia or worse D.C. I will sometimes take the long way and drive through the Gap just to get the cold chills of reflecting on all the men who came the same way. What was it like to be one of Jackson's Foot Cavalry on the way to Manassas? What was it like to be a Yankee Soldier watching Jackson's Foot Cavalry come at you? Or be with Mosby, either as a rider or a prisoner, etc.?