Mount Vernon Furnace - Credit: Wikimedia Commons
Mount Vernon Furnace, also known as Jacob's Creek Furnace and Alliance Iron Works, is a historic iron furnace located at Bullskin Township, Fayette County, Pennsylvania. It was built in 1795 and rebuilt in 1801. It is a stone structure measuring 24 feet square and 30 feet high, with two arches. It was built as a blast furnace and went out of blast in 1825. Note: This includes Read more on Wikipedia
Source: en.wikipedia.org