Cerreg Cennen, near Llandeilo, is a castle that was pulled apart by 500 men so it couldn’t be used as a base for robbers. It is built on a limestone crag, immediately above a deep natural cave.

Carreg Cennen
The Chapel of St Non, on the cliffs immediately south of St David’s, was built in 1934. It contains in its walls the last remnants of some of the many religious buildings that were scattered there from the 6th century until the Reformation, and the dissolution of the monasteries. Large circular stone piscines feature heavily. These were used to prevent the wine of the Eucharist – believed to be the blood of Jesus – from disappearing into the soil. There’s a project here, to depict the various starting points of the wall’s ingredients. Services are no longer held there, as rain is driven through the 2 foot thick walls within half an hour.
Nearby is St Non’s original ruined chapel, which in turn is supposedly built on the site of her house where she gave birth to St David:
The pain of birth was said to have been so intense that Non’s fingers left marks as she grasped a rock and, as David was born, a bolt of lightning is said to have split the rock in two. It is also believed that the two split pieces of rock were the foundation stones for St. David’s Cathedral and St Non’s Chapel. (Wikipedia)

St Non's Chapel
The chapel is surrounded by standing stones.
St David’s itself was repeatedly attacked and pulled apart by Viking raiders: “A visitor in the 11th century found only an abandoned site with St David’s shrine lost amongst the undergrowth.” (www.stdavidscathedral.org.uk)