These hills on the edge of the Bannau Brycheiniog (Brecon Beacons) were rich with coal, limestone and iron ore — the fuel of the Industrial Revolution.
Roedd cyfoeth o lo, calchfaen a mwyn haearn – tanwydd y Chwyldro Diwydiannol –yn y bryniau hyn ar gyrion Bannau Brycheiniog.