 Canterbury is a popular tourist destination : consistently one of the most @-@ visited cities in the United Kingdom , the city 's economy is heavily reliant upon tourism . The city has been occupied since Paleolithic times and served as the capital of the Celtic Cantiaci and Jute Kingdom of Kent . Many historical structures fill the area , including a city wall founded in Roman times and rebuilt in the 14th century , the ruins of St Augustine 's Abbey and a Norman castle , and the oldest extant school in the world , the King 's School . Modern additions include the Marlowe Theatre and the St Lawrence Ground , home of the Kent County Cricket Club . There is also a substantial student population , brought about by the presence of the University of Kent , Canterbury Christ Church University , the University for the Creative Arts , and the Girne American University Canterbury campus . Canterbury remains , however , a relatively small city in terms of geographical size , when compared with other British cities . 
