Iron forge at Fontenay Abbey dating from 1220. The Cistercians were well-known for their expertise in water engineering, and at Fontenay it was used to especially impressive ends. The monks extracted iron ore from stone quarried on the hill above the monastery, then used the forge to make iron tools to be sold in the region. This was the first metallurgical factory in Europe and the place of invention of the hydraulic hammer, which became the basis of industrial manufacturing in Europe. The forge was recently reconstructed based on the medieval original.