When you arrive at the door and see that the sanctuary knocker looks like this, you know that the rest of Durham Cathedral is bound to be interesting.
Durham's Cathedral Church of Christ and Blessed Mary the Virgin is the last resting place of: St Cuthbert - the greatest of the early English saints; St Bede - the finest scholar of his age; and the head of St Oswald - the warrior king and martyr. In addition, it was for centuries both home for a community of Benedictine monks and seat of the mighty Prince Bishops of Durham. (. . .) The cathedral building - a large part of which dates back some 900 years - is widely regarded as one of the most complete and perfect examples of Romanesque architecture still in existence.
That's from the introduction page of the Durham Cathedral and Castle website. The cathedral tour at that site is a treat: decently well organized and detailed. (There's even a glossary!)
Durham Cathedral contains the tombs of St Bede and St Cuthbert. There was a monastery at Durham for 450 years, until England's eternally annoying reformers forced the monastery's dissolution in 1540.
Related links:
Durham Cathedral (official website)
Durham Cathedral - great buildings online
photos of Durham Cathedral
Durham Cathedral History - from North East England History Pages
Interactive map of Durham Cathedral
The Venerable Bede - from the Catholic Encyclopedia
St Cuthbert - from the Catholic Encyclopedia