Caerphilly Castle is a medieval fortification constructed by Gilbert de Clare in the 13th century. 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 and is the largest castle in Wales and the second-largest castle in the United Kingdom after Windsor Castle. It is famous for having introduced concentric castle defences to Britain and for its large gatehouses.
Gilbert began work on the castle in 1268 following his occupation of the north of Glamorgan, 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 core of Caerphilly Castle, including the castle's luxurious accommodation, was built on what became a central island, surrounding by several artificial lakes, a design Gilbert probably derived from that at Kenilworth. The dams for these lakes were further fortified, and an island to the west provided additional protection. The concentric rings of walls inspired Edward I's castles.
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. The Marquesses of Bute acquired the property in 1776 and under the third and fourth Marquesses extensive restoration took place. In 1950 the castle and grounds were given to the state and the water defences were re-flooded. In the 21st century, the Welsh heritage agency Cadw manages the site as a tourist attraction.
References:The Broch of Gurness is an Iron Age broch village. Settlement here began sometime between 500 and 200 BC. At the centre of the settlement is a stone tower or broch, which once probably reached a height of around 10 metres. Its interior is divided into sections by upright slabs. The tower features two skins of drystone walls, with stone-floored galleries in between. These are accessed by steps. Stone ledges suggest that there was once an upper storey with a timber floor. The roof would have been thatched, surrounded by a wall walk linked by stairs to the ground floor. The broch features two hearths and a subterranean stone cistern with steps leading down into it. It is thought to have some religious significance, relating to an Iron Age cult of the underground.
The remains of the central tower are up to 3.6 metres high, and the stone walls are up to 4.1 metres thick.