Conwy's medieval town walls are magnificent. 11m high and 2m thick, they girdle the town on three sides and boast 22 towers and 3 gateways. In the High Street, at the corner of Crown Lane, is Plas Mawr, a superb mansion built in 1577. Aberconwy House, a medieval town house of c 1300, is a must-see. It contains an interesting exhibition on the history of the town. On the quayside nearby is what is claimed to be the "Smallest House in Great Britain".