Facing the cathedral across Palace Green, Durham's stately, manorlike castle commands a strategic position above the River Wear. For almost 800 years the castle was the home of the enormously powerful prince-bishops; from here they ruled large tracts of the countryside and acted as the main line of defense against Scottish raiders from the north. Henry VIII was the first to curtail the bishops' autonomy, although it wasn't until the 19th century that they finally had their powers annulled. The castle was given over to University College, part of the University of Durham (founded 1832), the oldest in England after Oxford and Cambridge. You can visit the castle only on a 45-minute guided tour. Times can vary, especially on summer afternoons, when the building can be hired out for private events, so it's best to call ahead. During university vacation time, the castle also offers bed-and-breakfast accommodations in the state rooms for around £195 per night; call or check the website for details.