Thankyou for the local info and links!

That being said, I recognize that DC is a city of secrets and I wouldn't discount anything - but I thought there should be some better understanding of the geography to inform opinion.

If this was any other city but DC, I wouldn't put so much weight into this theory - but with it being so close to the known/public underground tunnels + rumoured to be next to a huge private govt/military system I thought the possibility was worth mentioning.. Thanks again :)