The slate landscape of north-west Wales could join the likes of the Grand Canyon and The Great Barrier Reef after being nominated for world heritage status.
The area - which runs throughout the county of Gwynedd - is said to have “roofed the 19th century world” as slate from its mines was exported around the globe.
The landscape was assessed by a UK panel of experts this summer and it will be formally presented to UNESCO next year.
It will then be considered by the International Council of Sites and Monuments followed by the World Heritage Committee in 2021.
The site was the world’s greatest exporter of slate during the mid 19th century, becoming a key part of the social and economic fabric of North Wales. The slate mined from the area also had a significant impact on global architecture with its materials used on a vast range of buildings, from terraces to palaces all around the world.
If inscribed it would be the fourth World Heritage Site in Wales, alongside the Blaenavon Industrial Landscape, the Castles and Town Walls of King Edward at Gwynedd and the Pontcysyllte Aqueduct.
The UK currently has 31 other World Heritage sites and can nominate one site per calendar year.