Beginning in 1834, the iron furnaces at Greenwood dominated this otherwise rural landscape, and for most of 70 years one or both of the two furnaces here lit the night with a fiery, multi-colored glow. Wood-choppers harvested vast tracts of forest for charcoal, colliers slow-burned logs into charcoal, miners dug tons of nearby iron ore, and wagons hauled limestone from quarries over the mountain. Greenwood’s owners built two furnaces: the first, on the left, roared to life in 1834, rose 30 feet above a 30-foot square base, and operated until 1880; the second, on the right, went into blast in 1867 and operated until 1904. Surrounded by wooden buildings and machinery that fanned the fire to 3,000 degrees Fahrenheit, the flat-topped stone furnaces formed a major industrial presence in the valley. The second furnace, with a daily capacity of 12 tons compared with the first furnace’s 4 to 5 tons, ranked as one of the largest cold-blast charcoal furnaces ever built and one of the last to operate in Pennsylvania. When the last fire went out in furnace #2 in 1904, that industrial presence disappeared from the valley, and the forests slowly returned, aided by seedlings grown at Greenwood Nursery established after the furnace closed.