Movies filmed in Llechwedd Slate Caverns, Llechwedd Slate Mine, Blaenau Ffestiniog, Gwynedd, Wales, UK

There are 3 movies that were filmed in Llechwedd Slate Caverns, Llechwedd Slate Mine, Blaenau Ffestiniog, Gwynedd, Wales, UK.
The Black Cauldron
(1985)
Prince Valiant
(1997)
Merlin and the War of the Dragons
(2008)