Hatstand said:
Or even Porthmadog and Blaenau Ffestiniog... tut!
Only Porthmadog since 1974, it was called Portmadoc before then! (bloody PC crowd rewriting history) And the good old FR calls itself the Festiniog Railway by Act of Parliament.... :tease:
(see you tomorrow BTW!)
And back on topic, I would recommend Cwmorthin, getting the access code from Friends of Cwmorthin.
And if feeling adventurous, one could try the Rhosydd through trip, in the 9 adit, up the backfilled chambers to the right hand side of the incline, then climb out the left hand side of the Twll. You could also find your way to the Croesor link and as SamT says, admire the huge underground lake. Note you can't see any water if you enter Croesor from the Croesor side as the first chamber is just full of boulders.
Or if you want proper caving, you can visit Ogof Hen Fynhonnau (Poachers) or Ogof Hesp Alyn. Both have a ladder pitch at the entrance, but after that are great fun. Poachers is probably better as it has a lovely underground streamway.
Chris.