The tour of the medieval walls of Norwich was extremely instructive. We started at the Boom Towers adjacent to Carrow Bridge. These structures allowed a chain to be raised to restrict river traffic along the Wensum (although the position of the chain and winding mechanisms was not immediately clear). The damage to the tower since 1934 can be seen quite clearly here.
We climbed up the hill from the river inspecting the well preserved walls and towers along the south side. For an image of the tower in the 1930s see here.
Notice the wall walk and the way that the staircase is mounted into the wall.
We crossed the river to inspect this terminal bastion adjacent to the river in the northern part of the circuit.
Further details about the medieval walls of Norwich can be found here. A photographic record of the walls can be found here.