Substantial remains of Newcastle's medieval defensive wall survive around the western and northern edges of the city centre. The best-preserved sections run along the back of Stowell Street (Chinatown) and West Walls, where you can still see the wall walk and several towers — Heber Tower, Morden Tower, and the Half Moon Battery in particular.
A self-guided walk along the surviving sections takes about an hour and gives a strong sense of the medieval city's footprint. Most of the towers are open seasonally; the Morden Tower has hosted poetry readings since 1964.