The World Heritage Site at Blaenavon has an excellent range of landmarks from the Industrial Revolution. The mighty iron foundry which formed the cutting edge of technology only a short time ago, is now being lovingly restored and interpreted.

More than 40% of the World Heritage Site (WHS) falls within the National Park. The focus of the WHS is the head of the Afon Lwyd river which includes the major preserved items of Blaenavon Ironworks and Big Pit together with Blaenavon town and the oldest areas of iron and coal extraction between Blaenavon and Pwll-Du.

At Big Pit you can actually go down a coal mine guided by men who until recently earned their living at the coalface. Then you can explore the landscape around dotted with the remains of this era and imagine the hillsides teeming with the efforts of men, women, children and horses.

Blorenge Mountain has remains of limestone quarries, primitive railways and Garn-Ddyrys forge on its flanks.

Gilwern Hill had quarries which provided limestone, an essential material in the iron making process. Hill's Tramway was used to transfer quarried material to Blaenavon Ironworks through Pwll-Du tunnel and down to the Monmouthshire and Brecon Canal for onward transportation to surrounding areas.

Between Blorenge Mountain and Gilwern Hill lies Cwm Llanwenarth, a deeply cut valley revealing a pattern of smallholdings, farms and fields which predate the Industrial Revolution.