A small sign on the rubble wall below the tenement corner names it: the Flodden Wall. For all the traffic of visitors on the steps, few stop to read it.
Turn round at the top for the view that brings most people here. The castle rises on its rock straight ahead, over the rooftops and chimneys of the Grassmarket, and through a narrow slit in the old parapet you can frame it just as a defender once framed the ground below. Then follow the high rubble wall south along Heriot Place, with the school grounds hidden behind it, and you are walking the old edge of the town.