Where is Caerphilly Castle?

Caerphilly Castle is a medieval fortification in Caerphilly in South Wales. The castle was constructed by Gilbert de Clare in the 13th century as part of his campaign to maintain control of Glamorgan, and saw extensive fighting between Gilbert, his descendants, and the native Welsh rulers. Surrounded by extensive artificial lakes – considered by historian Allen Brown to be "the most elaborate water defences in all Britain" – it occupies around 30 acres (12 ha) and is the largest castle in Wales and the second-largest castle in the United Kingdom after Windsor Castle.

Famous for having introduced concentric castle defences to Britain and for its large gatehouses. Gilbert began work on the castle in 1268, with the majority of the construction occurring over the next three years at a considerable cost. The project was opposed by Gilbert's Welsh rival Llywelyn ap Gruffudd, leading to the site being burnt in 1270 and taken over by royal officials in 1271. Despite these interruptions, Gilbert successfully completed the castle and took control of the region.

The dams for these lakes were further fortified, and an island to the west provided additional protection. The castle was attacked during the Madog ap Llywelyn revolt of 1294, the Llywelyn Bren uprising in 1316 and during the overthrow of Edward II in 1326–27. In the late 15th century, however, it fell into decline and by the 16th century the lakes had drained away and the walls were robbed of their stone.