Roman Glevum, royal burial site, and the cloisters that inspired Hogwarts
Gloucester is a Roman city with a cathedral whose cloisters were used as filming locations for Hogwarts in the Harry Potter films — and those cloisters happen to be the finest perpendicular Gothic cloisters in England, built between 1370 and 1410. The cathedral contains the tomb of Edward II (murdered at nearby Berkeley Castle in 1327) which became a major pilgrimage site, funding the extraordinary Perpendicular Gothic reconstruction of the building. The city has a working Victorian docks complex — one of the most complete in Britain.
Gloucester was the Roman colonia of Glevum, one of only four Roman coloniae in Britain (with Colchester, Lincoln, and York) — places of the highest Roman civic status, settled by retired legionary veterans and granted full Roman citizenship. The Norman castle was where William the Conqueror commissioned Domesday Book and where Henry III was crowned as a nine-year-old in 1216 (Westminster was in rebel hands). The cathedral's position as a royal burial site — Edward II is here, Robert Curthose (William the Conqueror's son) is here — drove the extraordinary Gothic building campaign.