Kidwelly Castle stands as one of Wales' best-preserved medieval fortress complexes, showcasing an innovative 'castle within a castle' design from the Norman era through medieval expansion. Begun as a simple 12th-century ringwork with earthen defenses, it was repeatedly contested by Welsh princes including the powerful Lord Rhys who captured it in 1159. By the 1280s, the Chaworth brothers transformed it into the impressive stone structure visible today, featuring remarkable architectural elements including corner towers, a south gate complex, chapel tower, and fortified upper ward. Strategically sited where the River Gwendraeth reaches its lowest bridging point, Kidwelly represents one of Wales' finest examples of medieval secular architecture, managed by Cadw and notable for surviving without significant early modern alterations.