This very ordinary possible staircase(only the bottom few steps remain)is one of only a few such remains on the line of Hadrian's Wall.It is from this unassuming piece of archaeology that it has been possible to estimate the height of the wallwalk.By projecting the angle of the stairs upwards,experts have come up with the accepted height of 15 ft. for the wallwalk.Sadly,no part of the Wall now exists to that height,so the calculation remains an estimate.