Nevern Castle (Castell Nanhyfer)

Most Pembrokeshire castles were built to hold the Welsh down; Nevern is one of the rare ones built by the Welsh — the Lord Rhys took it in 1191 — and archaeology here uncovered one of the earliest stone castles in Wales. What survives is earthworks, ditches and low walls in a beech wood above the village, free and always open, with interpretation boards that do the imagining with you.

The village below earns the stop on its own: St Brynach's churchyard holds a magnificent eleventh-century Celtic cross and the famous "bleeding yew", which drips blood-red sap and has done for as long as anyone can say. Together with Pentre Ifan ten minutes away and Castell Henllys up the valley, Nevern anchors the best ancient-history cluster in Wales — all of it within Newport's orbit, and most of it free (more free days out here).