Bangor Cathedral

Stone walls dating back to the 6th century rise from Bangor's heart, making this the oldest cathedral site in Britain. The current building might look modest from outside - no soaring spires or gothic grandeur here - but step through those doors and you're walking where monks have prayed for over 1,400 years. That's proper old.

History buffs will love the medieval bits that survived Henry VIII's dissolution, particularly the carved choir stalls and some cracking 16th-century woodwork. The Mostyn Chapel houses the tomb of Owain Gwynedd, a Welsh prince who gave the English a right headache in the 12th century. Kids might find it a bit dry unless they're into stories of ancient kings and Viking raids.

It's free to enter, which is always a bonus, and you can easily see everything in under an hour. The cathedral sits right in Bangor town centre, so combine it with a wander down the high street or a quick coffee before heading back to your park. From Plas Coch Holiday Park or Taihirion Farm Campsite, it's barely five miles - perfect for a rainy afternoon when the beach loses its appeal.

Open most days until 4:30pm, though they close early on Friday and Saturday. Worth checking before you make the trip.