Michael Portillo takes the train to the medieval walled town of Conwy on the last leg of his exploration of the shores of north Wales.On a coastal ridge overlooking the estuary of the River Conwy is the town's impressive 13th-century castle, built by the conquering English king, Edward I, on the site of palace of the Welsh prince, Llywelyn.In the foothills of the Carneddau mountain range, Michael enjoys breathtaking views over 27,000 acres of rugged open land. The Victorian resort of Llandudno is Michael's next stop, where he scales the dramatic limestone headland to investigate one of the most important Bronze Age copper mines in Europe.Michael presses east to reach Colwyn Bay. Its long sweeping promenade looks out over Liverpool Bay and the Irish Sea beyond, but alongside the holidaymakers, Michael finds bulldozers and computer guided earth movers engaged in a transformational project to create a new beach.