An arch.

Headed to the Cowgate from work tonight, heading for yet another drinking sesh (thankfully I cut this one very short, I don't think I have the stomach for it) and I was taking pretty much the most direct line I could manage - albeit one that didn't involve climbing over Edinburgh Castle, so I ended up on King's Stable Road, with this really nice tunnel/arch thing.

Then a ned came past on a BSO and looked like he was thinking of mugging me, so I got paranoid and left sharpish.