Well looks like I am working in Swansea for a month so I wanted to know if anything underground and no more then 1hr out of Swansea was worth visiting.

Show caves as well as simple holes in the ground to mines to any regular trips during the week welcome.

Let's see now;

Anything in the Swansea valley- OFD, Dan-Yr-Ogof, Pwll Dfyn, Tunnel and Pant Mawr Pot to name but a few.

Llethrid Swallet on the Gower-well worth a trip.

All the caves around Ystradfellte are probably within an hour of Swansea, so Porth-Yr-Ogof is a must. Dinas silica mines as well.