At the northern end of Portsmouth cove, a castle that is almost entirely surrounded by the sea. The first stage of its construction was undertaken in the late 3C, during the Romans. The walls still stand, although the fort was used by the Saxons in the 5 and 6C before becoming a medieval castle in the early 12C under the reign of Henry I.

The displays are devoted to local history and arts from the 17 to the 20C.

Less grand than Fishbourne, the Roman Villa is more of a noble's house than a palace but it has some exceptionally fine mosaics, notably the Ganymede mosaic in the piscina, a Head of Venus and the chillingly austere Winter, in the north wing and a Medusa Head in the bathhouse.

The cathedral took over a century to build (1091-1184) and has traces of every architectural movement of the Middle Ages. The nave is Norman, the porches, retro-choir and tall windows are Early English; the tower, side chapels and Lady Chapel are in Decorated style while the cloister, bell tower and splendid spire (rebuilt in 1861) are Perpendicular.