Caer y Twr Hillfort

Scrambling up Holyhead Mountain on a grey morning, the ancient stone ramparts of Caer y Twr emerge from the mist like something from a fantasy film. This Iron Age hillfort, perched 220 metres above sea level, commands proper views across the Irish Sea - on clear days you can spot the Wicklow Mountains.

What remains today are the substantial stone walls that once protected this clifftop settlement, probably built around 200 BC. The fort's defensive position is obvious once you're up there - sheer drops on three sides made it virtually impregnable. Walking the circuit of the walls takes about twenty minutes, though you'll want longer to appreciate the setting.

History enthusiasts will find plenty to ponder, but it's the location that really delivers. The climb from Holyhead takes roughly 45 minutes and isn't too taxing, making it manageable for older children. That said, younger kids might find the walk up a bit of a slog with limited reward once they reach the top - there's not much left beyond those atmospheric stone walls.

Free to explore whenever you fancy, though the exposed hilltop can be brutal in bad weather. If you're staying near Holyhead at places like Silver Bay Holiday Park or Sandy Beach Caravan Park, it makes for a decent morning's adventure before hitting the beach. Just don't expect Caerphilly Castle - this is archaeology for purists.