Molleaen, the 12 km long Mill Stream, north of Copenhagen, powered nine mills, and was for many centuries one of the reasons for the prosperity of the Danish capital. It has been called the Cradle of Danish Industry. The various mills were used for grinding grain, fulling woollen cloth, making gunpowder, working brass and copper, and producing hardware for sale in Copenhagen’s ironmongers’ shops. A large windmill was erected alongside one of the mills in 1814, and now forms the only in situ exhibit in the open-air museum, which is part of the national museum, as is the mill at Brede. The latter is part of one of the best-preserved factory colonies in Denmark, dating from the early 20th century and established by a textile concern that occupied the mill between 1832 and 1956.