Dyfi Furnace is a compact but evocative piece of Welsh industrial history: an eighteenth-century charcoal-fired blast furnace built to smelt iron using local timber, water power, and imported ore. The surviving stone furnace and wheelpit sit in a wooded valley setting that makes the technology easy to picture.
It is a short visit, but a worthwhile one if you are exploring the Dyfi valley by car or combining it with nearby nature reserves and mountain roads. Interpretation is limited compared with a full museum, so it helps to read up briefly before going.