Caerphilly Castle (Welsh: Castell Caerfili) is a Norman castle that dominates the centre of the town of Caerphilly in south Wales. It is the largest castle in Wales, the second largest in Britain (second to Windsor castle) and is one of the largest fortresses in Europe. Built mainly between 1268 and 1271, it is an early example of a concentric castle and is surrounded by large but fairly shallow artificial lakes to slow attackers and prevent the undermining of its walls. Caerphilly Castle in south Wales is one of the largest castles in the United Kingdom. It was built by Gilbert de Clare between the years 1268 and 1271. By 1267 Llywelyn ap Gruffydd, the last native prince of Wales, had become lord of the greater part of Wales. He posed a threat to de Clare, the Anglo Norman lord of Glamorgan and the castle was built in response to this threat.
Caerphilly is considered to be the earliest and finest example of of the true regular concentric fortification in the British Isles. The water defences are thought to be modelled on those of Kenilworth Castle. Visitors will be interested to see the collection of massive siege engines, based on known early examples.