Cardiff Castle is two things: a Norman motte-and-bailey castle from the 11th century, and a Victorian Gothic fantasy apartment built inside it for the Marquess of Bute in the 1860s. The interior of the Bute apartments is extraordinary, the Arab Room, the Chaucer Room, the Winter Smoking Room, all commissioned with unlimited budget and carried out by architect William Burges with maximum intensity.
The contrast between the bare Roman walls outside and the gilded interiors within is one of the more surreal experiences in any Welsh building. The guided tour of the apartments is essential for the full effect.