Beaumaris Castle on the Island of Anglesey. One of the 'iron ring' of North Wales. Menai Strait. UK

Beaumaris on the island of Anglesey is famous as the greatest castle never built. It was the last of the royal strongholds created by Edward I in Wales - and perhaps his masterpiece.
Here Edward and his architect James of St George took full advantage of a blank canvas: the ‘beau mareys’ or ‘beautiful marsh’ beside the Menai Strait. In pure architectural terms Beaumaris, the most technically perfect castle in Britain, has few equals. Its ingenious and perfectly symmetrical concentric 'walls within walls' design, was state of the art for the late 13th century.
Beaumaris Castle was never fully built, but had it been completed it would probably have closely resembled Harlech Castle. Both castles are concentric in plan, with walls within walls, although Beaumaris is the more regular in design. Historian Arnold Taylor described Beaumaris as Britain's "most perfect example of symmetrical concentric planning" .Beaumaris was as much a royal palace and symbol of English power as it was a straightforward defensive fortification. Nonetheless, the castle is praised by UNESCO as a "unique artistic achievement" for the way in which it combines "characteristic 13th century double-wall structures with a central plan" and for the beauty of its "proportions and masonry".
choice by k.khuhawar