Castell

Iron Age fortifications don't get much more dramatic than this clifftop stronghold perched above the Irish Sea. What remains of Castell - also known as Caer y Twr - sits on the summit of Holyhead Mountain, offering one of the finest viewpoints on Anglesey. The walk up takes about 45 minutes from the nearest car park, and it's proper steep in places, but the panoramic views across to Ireland make every huffing step worthwhile. Stone walls and ramparts still mark out the ancient settlement's boundaries, though you'll need a decent imagination to picture how it looked 2,000 years ago. History enthusiasts will appreciate the site's strategic importance - controlling the approach to Holyhead harbour from this vantage point made perfect sense. Families with older children who don't mind a decent hike will love it, though the exposed clifftop location means it can be wickedly windy even on calm days. The ruins themselves won't detain you for more than 30 minutes, but most visitors end up lingering far longer just soaking up those views. It's free to explore and accessible year-round, though winter visits require proper waterproofs. From nearby holiday parks like Sandy Beach or Silver Bay, it makes a cracking half-day excursion that'll give the kids something to boast about back home.