Cow Tower is a compact but memorable remnant of Norwich's medieval defences, a round brick artillery tower built beside the River Wensum. Its open shell and thick walls show the moment when city fortifications were adapting to gunpowder, and the riverside setting makes it far more atmospheric than its modest size suggests.
It is an easy detour from Norwich Cathedral and the riverside path. You do not need long here, but the tower helps explain Norwich as a wealthy medieval city with something to protect. The best approach is on foot, following the river where the surviving masonry, water and cathedral close all sit within a few minutes of each other.