The largest castle in Wales, ringed by wide artificial lakes, with a tower that leans further than the one at Pisa
Open to visitorscheck opening times and admission before you go
Substantial ruinsruined, but plenty survives above ground
Caerphilly is the biggest castle in Wales and one of the largest in Britain, and the thing that makes it work is water. Gilbert de Clare, a powerful Norman lord, began it in 1268, and rather than sit it on a hill he spread it across low ground and dammed the streams to flood the surroundings, so the castle sits behind a series of wide artificial lakes crossed by stone causeways. Those water defences, along with the concentric walls set one inside another, made it very hard to attack, and they still give you the best view of the place as you approach across the dams.
The other thing everyone notices is the leaning tower at the south-east corner, which tips out at an alarming angle, further off vertical than the famous tower at Pisa. It was left leaning after the castle decayed and later partial explosions, and it has stayed that way ever since. Caerphilly is looked after by Cadw, and the reconstructed great hall and the fired-up siege engines on the grounds help make sense of how a castle this size functioned.
The castle stands in the middle of the town of Caerphilly, so it is easy to reach by train from Cardiff, and there is plenty of space to walk around the lakes. If you are making a day of the local castles, the fairytale Castell Coch is a short way south, and the Taff Trail passes nearby for walkers and cyclists.
