Little now remains of Oxford Castle, which was built for William the Conqueror in 1071, and largely destroyed after the English Civil War because the defeated Royalists had used it as a prison. Entertaining theatrical tours, though, led by costumed guides and departing every 20 minutes in peak season, now lead through the parts that survive – including prison cells which quite unbelievably remained in use until 1996 – and provide an enjoyable overview of Oxford’s extraordinary history.

　　St George's Tower, where the tours begin, is Oxford’s oldest building, erected to keep out Vikings around 1009, as one of four towers on the city walls. You continue to the 11th-century crypt of St George's Chapel, possibly Oxford's first formal teaching venue, and the 18th-century Debtors' Tower, to learn about the grisly lives, daring escapes and cruel punishments of various Victorian inmates.

　　With your tour ticket, or simply by paying £1, you can also clamber up the castle’s original medieval motte nearby, an artificial hill built by 200 Saxon slaves that’s now just a grassy mound, topped by two spreading trees.