I can give only a brief description of the town.  It is surrounded by a wall twelve feet thick, and a mile and a quarter in length, having twenty-seven towers and battlements.  One of them is called Llewellyn's. It is entered by five gates, three principal, and one postern; and another has been formed to admit a suspension-bridge across the river, similar to that constructed by Mr Telford across the Menai Straits. Mr Stephenson also designed the tubular bridge through which the Holyhead railway passes.  The town contains some very picturesque houses, built in the time of Elizabeth.