Builth Castle (Welsh: "Castell Llanfair-ym-Muallt" ) was a castle built under King Edward I, just outside Builth Wells, Powys, Wales. At one time it was an impressive stone-built castle but all the masonry has been removed over the years and all that remains are the mound on which it stood, the ditches and embankments.
The masonry of Builth Castle has been destroyed. 
The masonry was removed, but it doesn't mean it was destroyed. It could have been stored in a museum or such.