Caernarfon Castle is a medieval fortress in Gwynedd, North Wales.Caernarfon Castle is recognised around the world as one of the greatest buildings of the Middle Ages.This fortress-palace on the banks of the River Seiont is grouped with Edward I’s other castles at Conwy, Beaumaris and Harlech as a World Heritage Site. But for sheer scale and architectural drama Caernarfon stands alone.Here Edward and his military architect Master James of St George erected a castle, town walls and a quay all at t