Caerphilly Castle is simply enormous. Huge. It is the largest castle in Wales and the second-largest in Britain, after Windsor. It covers a 30-acre site and is a mass of concentric defensive walls, surrounded by moats and artificial lakes. It was built by the Norman Gilbert de Clare, known as Gilbert the Red for his red hair, mainly between 1268 and 1271, in order to subdue the Welsh - and it still dominates the area. The castle declined as it became redundant and it was rescued from total ruin by the Bute family in the 19th century.