Harlech Castle is one of the four great castles in Wales that was constructed for Edward I. It is a World Heritage site and was built between 1283 and 1289. The castle is spectacularly situated on a rocky outcrop and is defended by sheer cliffs on its seaward side, with the remainder protected by a deep moat. It has an impressive inner curtain wall with huge round towers on the corners. Some would argue that this is the most beautiful castle in Wales.