Just mention Canterbury and most people are taken back to memories of high-school English classes and Geoffrey Chaucer's Canterbury Tales, about medieval pilgrims making their way to Canterbury Cathedral. Judging from the tales, however, in those days Canterbury was as much a party town as it was a spiritual center.
The city has been the seat of the Primate of All England, the archbishop of Canterbury, since Pope Gregory the Great dispatched St. Augustine to convert the pagan hordes of Britain in 597. The height of Canterbury's popularity came in the 12th century, when thousands of pilgrims flocked here to see the shrine of the murdered archbishop St. Thomas à Becket. This southeastern town became one of the most visited in England, if not Europe. Buildings that served as pilgrims' inns (and that survived World War II bombing of the city) still dominate the streets of Canterbury's center, though it's tourists, not pilgrims, who flock to this city of about 40,000 people today.
Prices at city museums are higher than average, so if you plan to see more than one, ask at the tourist office if a combination ticket might be cheaper.