The Carrie Blast Furnaces are a rare surviving example of pre-World War II iron-making technology. This National Historic Landmark, part of the Rivers of Steel National Heritage Area, offers guided tours that provide a fascinating glimpse into Pittsburgh's industrial past. Visitors can walk among the colossal furnaces and learn about the steelmaking process, the lives of the workers, and the impact of the industry on the region. It's a powerful and unique educational experience.