Bangor Cathedral occupies the valley floor at the centre of the city, its modest bulk flanked by a pedestrianised high street on one side and a hillside garden on the other. The diocese was founded by Saint Deiniol around 525 AD, giving Bangor one of the oldest claims to continuous Christian worship in Britain — though the building you see today is largely a Victorian reconstruction.
Inside, look for the wooden choir stalls, a fragment of medieval encaustic tile, and the tomb of Gruffudd ap Cynan, King of Gwynedd, who died in 1137. The cathedral garden behind the building is peaceful and well maintained, with views up the hillside toward Bangor University's Gothic revival buildings. The cathedral is open daily and admission is free.