Those who love castles - and Wales has lots to choose from - will probably enjoy this recent article from Mental Floss. However be warned, although splendid, all of the castles are ruined and not lived in.
I been to all of them over the years and all are worth visiting. Conwy is still my top favourite. Most castles are empty inside. Not Conwy. The walls of the internal buildings still stand giving a feel for what the castle would have ben liked (and how cramped it might have seeemed.)
There are so many ruined castles in Wales and so many that haven't been included in this list - Raglan, which must be one of the largest castles in Wales and Carreg Cennan with its passageway cut down through the cliff it stands on. And of course there is the wonderfully restored Castell Coch - everyone's dream of a fairy tale castle...