National Slate Museum right outside of town and you can take a train up Snowdon or walk, if you have planned well or had lots of time. We didn't. There were no train tickets because they'd all been sold out; and we didn't think ahead to buy them before. Nor did we have the time we would have needed to climb up.
Dolbadarn Castle, which is supposed to be typical of a Welsh castle before the English invasion in that it's quite small (especially compared to, say, Caernarfon Castle!), round, and on a hill. It looks like there are ruins around it from smaller stone buildings.
All in all, we had a gorgeous day, as you can see from my pictures with the almost unreal blue sky.
(Yes, we did visit Caernarfon Castle during this day, too, and it was HUGE, and amazing, and ingenious with arrow shooting slits that LOOK from the outside like ten slits, but in reality provide space for 3 archers each, each shooting from a different angle.)
While I was sitting on this little wall, waiting for the sheep in the first picture to get a little closer (they didn't) or move somewhere interesting (they did, I think), I talked with another woman about my age, also with a camera and an interest in photography about the difficulty of going to the same beautiful spot that other people have gone to for years and trying to take a picture that feels special or unique in some way. She'd set herself a task for the day of trying to take a picture that would capture the feeling of the autumn in Wales that day, which seemed a difficult thing because it was so green and beautiful that it didn't feel at all like autumn to me.
Still and all, Wales was beyond my expectations, and my expectations were pretty darned high!