Hopewell Furnace National Historic Site

"Operated by the National Park Service, this Historic Site is a relatively small landscape that showcases an 18th and 19th century iron plantation. There are a number of furnaces and historic structures, a barn, mansion, forge, blacksmith's shop, and a really cool water wheel, the purpose of which is to operate the billows that keep the forget blazing hot. There is a visitor's center, but we didn't go in. There is no admission, so visitors can wander around freely. I believe there are also re-enactors, although we didn't see any during our visit. It's certainly a lovely, education place to explore with the family for a day."