Pen y Cae is a small village in the Upper Swansea Valley, close to the southern edge of Bannau Brycheiniog, also known as the Brecon Beacons. The village itself is modest, but the immediate area has a surprisingly strong trio: caves, a country park, and a theatrical castle story.
The National Showcaves Centre for Wales is the main draw, with Dan yr Ogof and other limestone caves just up the road. Nearby Craig y Nos Castle was the home of Adelina Patti, the 19th-century opera star who built a private theatre in the valley.
Treat Pen y Cae as a compact day out rather than a base. It works well if you are already moving between Swansea, Brecon, and the waterfall country to the east.