yeah, Vlad, "the Valleys" is usually taken to refer to the heavily industrialised area of Wales that stretches from eastern Carmarthenshire, straight through Glamorgan and into Gwent. it's very hilly and the industries expanded along the bottoms of the valleys that cut into the hills.

Lots of coal and metal ores see, boyo.

There are plenty of other valleys in Wales but they are not "The Valleys".