Sloss Furnaces National Historic Landmark is a 32-acre blast furnace plant where iron was made for nearly 100 years. Now a museum of history and industry, the site preserves an extraordinary collection of buildings, industrial structures and machinery. Sloss is the only 20th century blast furnace in the country that is being preserved and interpreted as a museum. Sloss hosts a wide variety of concerts, festivals and conferences. Closed on Mondays. Free Admission.