Conwy is one of the best-preserved medieval walled towns in Britain. The town walls, built by Edward I in the 1280s as part of his ring of fortresses across north Wales, still encircle the old town almost completely — you can walk the full circuit of the battlements and look down into the streets below. Conwy Castle itself is an impressive hulk of towers and great halls perched above the estuary, and along with the walls it forms a UNESCO World Heritage Site.
The town is small enough to cover on foot in a morning, with a compact centre of old stone streets, a good quayside, and the claim to fame of the Smallest House in Britain (genuinely tiny, on the quay). Plas Mawr, the Elizabethan townhouse near the castle, and Aberconwy House, the only surviving medieval merchant's home in town, are both worth an hour of your time. Thomas Telford's elegant suspension bridge sits in the shadow of the castle walls — a remarkable survival from 1826.
Conwy sits on the A55, the main north Wales coastal route, and is a natural stopping point between Llandudno and Bangor. The Holyhead ferry to Dublin is a few miles further west, making Conwy a convenient overnight stop on the Ireland crossing. The Conwy Valley Railway runs south from Llandudno Junction through spectacular scenery into Snowdonia.