Beaumaris Castle

The moment you round the corner in Beaumaris and spot those massive curtain walls rising from the grass, you understand why Edward I bothered building it. This is a proper castle, not some crumbling ruin - it's one of the finest concentric fortifications in Britain, and it looks almost deliberately perfect, like someone's architectural revenge plan made stone.

Walking the outer walls takes a good hour if you're not rushing. The inner ward is where the scale really hits you - towers at each corner, the gatehouse still commanding, the whole thing built on a geometric grid that feels almost obsessive. You can clamber up the towers for views across the Menai Strait. On a clear day you see right over to Snowdonia. It's the kind of perspective that makes you grasp why medieval military architects were properly clever.

History enthusiasts will spend half a day here without effort. Families with restless kids under ten might find an hour does it - there's only so much rampart-walking children will tolerate. The site's free to explore from the outside; check locally about paid entry to the interior towers.

Base yourself at Kingsbridge, Wonderfully Wild, or Plas Yn Llangoed - all within a couple of miles - and you've got a cracking spot for exploring Anglesey. Beaumaris town itself has decent cafes and you can walk down to the pier for a breather. It's worth the detour even if castles aren't normally your thing.