The beauty of the Brecon Beacons is well known, but in the middle of the 18th century it was not the beauty that drew man to the area. On the south eastern edge, where the mountains turn into the deep valleys of South Wales was an abundance of raw materials for the making of iron. From Hirwaun in the west to Blaenavon (now a World Heritage Site) in the east huge ironworks were built. The largest, by far, were the giants of Dowlais, Penydarren and Cyfartha, all in Merthyr Tydfil, which became the industrial capital of the world. From here iron was used in the Napoleonic Wars, the American Civil War and was used to build railways world wide, especially in the USA. This shallow quarry, situated on Cefn Cadlan, supplied the ironworks at Hirwaun, which opened in 1757.