Tenby Castle

The ruins of Tenby Castle command the headland above the harbour like a stubborn old guard who's seen better days. What remains is mostly the gatehouse and defensive walls - medieval stonework that's weathered centuries of Atlantic wind - but it's enough to give you a proper sense of the fortress that once controlled this stretch of Pembrokeshire coast.

You can wander the site freely, picking your way through the ruins and getting decent views back across the town and its beaches. It's not a grand affair - no vast halls or towers - but if you're already in Tenby (which you likely are, given it's practically on the seafront), it's worth the fifteen-minute detour. History types will appreciate the 13th-century origins and the strategic position. Kids might lose interest after half an hour unless they're keen on scrambling over old stones.

The walk up from the town centre is straightforward enough, though the final approach gets a bit steep. Free to visit, obviously - there's nothing to pay. Best done on a clear day when you can actually see the Carmarthen Bay views properly. On a drizzly Welsh afternoon, it's all rather moody and atmospheric, which has its own appeal.

If you're staying at Saltern Holiday Park or Haven Kiln Park right nearby, this is an obvious morning activity before hitting the beach. It fits naturally into a Tenby-based holiday without requiring any planning whatsoever.