Harnessing the power of the Ruhr, Lenne, Volme and Ennepe rivers drove Hagen’s development as a centre for the metalworking industry as early as the 15th century. The Westphalian Open-Air Museum in Hagen gives visitors an insight into the region’s handicraft and technical history. Today, the city’s economy is characterised by medium-sized metalworking companies. Hagen is the seat of Germany’s only state-owned distance-learning university, which with over 70 000 students is also the country’s largest university.