The forge in Frohnau is today the main attraction in this small town. It operated as a flour mill and later an oil mill. It was open from 1621 until 1904, and contains the huge Frohnauer Hammer. Today the mill houses the Frohnauer Hammer Museum of Technology, where visitors can come and see the landmark and learn about its use and the history of milling in Frohnau. The museum is open daily.