Built before 1230 by the Princes of Gwynedd, the keep of Dolbardarn rises like a perfect chessboard rook from a green hilltop between the two lakes, Llyn Padarn and Llyn Peris. If it seems spartan, spare a thought for Owain ap Gruffydd, imprisoned here for 20 years in the mid-13th century by his younger brother Llewellyn the Last. It's a brief stroll from town and you'll be rewarded with wonderful views of the lakes, quarries and Snowdon itself.
Dolbadarn Castle
Snowdonia National Park (Parc Cenedlaethol Eryri)