Purdown AA Battery preserves the remains of a Second World War anti-aircraft site on high ground above Bristol. The concrete structures are stark, but they make the city's wartime geography tangible in a way central plaques often do not.
It is a niche but worthwhile stop for military-history walkers or anyone exploring Stoke Park and Purdown. Go for the combination of ruins, open space, and views rather than expecting a staffed museum.