Harlech

The castle is still waiting for the tide. Harlech, on the coast of Gwynedd in North Wales, was built by Edward I on a crag with the sea at its foot, and the sea has since walked away across dunes and golf links, leaving the walls staring at sand with the mountains of Eryri at their back. Of the four castles he raised in the north, this is the one with the setting, and the town climbs the rock behind it by a lane so steep it held a world record.

Master James of St George built Harlech from ground to battlements in seven years in the 1280s, walls within walls on natural defences, and when Madog ap Llywelyn's rebellion cut it off the garrison was fed by sea up the Way from the Sea, a stair of 108 steps hacked into the rock face that you can still see. Owain Glyndŵr took the castle in 1404 and made it, with Machynlleth, the seat of his independent Wales, summoning a parliament and perhaps holding his coronation here; in the Wars of the Roses it endured a siege by seven thousand men before falling, and its defenders became the Men of Harlech of the song, which Zulu's garrison sang at Rorke's Drift. A footbridge now carries you into the castle as its architect intended, and with Conwy, Caernarfon and Beaumaris it holds World Heritage status. Ffordd Pen Llech, the lane that corkscrews down from the town under the walls, was certified the steepest street in the world in 2019 and lost the title the next year when Guinness ruled that gradients be measured along the centre line; it is still 28.6 per cent. The beach below is vast, backed by dunes that are a National Nature Reserve, with strong currents that the RNLI signs are frank about.