Set up in 1873, this factory produced only cast iron beams. Taken over by the Röchling family in 1881, it became a great industrial centre and assured all stages of production for cast iron and steel. For one century this factory employed more than 16000 people, thus keeping the town alive. The factory is now open to visitors and has been a Unesco World Heritage Site since 1994. The church of the Reconciliation with its fresco glorifying the site and the Röchling dynasty is also worth a visit.