Castles and Town Walls of King Edward in Gwynedd
For the 20th century, the castles and walls were mainly known for their military purpose. It is described as the "zenith of English castle-building" by  D. J. Cathcart King. It is because of the use of concentric defences, barbicans, and substantial gatehouses. Also, Sidney Toy considers them as "some of the most powerful castles of any age or country".