Marine and terrestrial deposits from the Cretaceous, Tertiary and Holocene periods have been preserved in karst caves in the mass limestone.Other fossil sites with animal and plant remains from the Palaeozoic to the Mesozoic have also made important contributions to geoscientific research.In the area around Hagen, for example, the bones of land dinosaurs and early mammals as well as plant remains from the Lower Cretaceous period were found.The former Hagen-Vorhalle brickworks quarry is considered an important site for the discovery of fossilised insects and other fossils, including early large dragonflies with wingspans of 40 cm, extinct primordial web-footed butterflies and giant centipedes and millipedes from the Upper Carboniferous period.By 1865, Hagen had overtaken Iserlohn, which had previously been the leading town in South Westphalia in terms of population and economic power.Through urbanisation and industrialisation of the 19th century, the city developed into the main centre for the entire region south of the river Ruhr.In the years following the turn of the century, the banker and patron Karl Ernst Osthaus brought many later important architects to the city, including Henry van de Velde, Peter Behrens and Walter Gropius.In reaction to the Kapp Putsch in March 1920, when rightists tried to overthrow the elected government and set up an authoritarian regime,[6] tens of thousands of leftist workers in the Ruhr Valley, Germany's most important industrial area, used the opportunity for a revolutionary uprising from the Left.Dozens of Hagen citizens were murdered in concentration camps and prisons for racial, religious, ideological and political reasons.A history teacher revealed a painted portrait of Adolf Hitler and medals decorated with eagles and swastikas, a newspaper from 1945, a pistol, gas masks, brass knuckles, and stacks of documents.Further job losses affected the food industry with the breweries Bettermann and Andreas, the confectionery manufacturers Villosa and Grothe and the production plant of Zwieback Brandt.Many well-known musicians and bands of this musical genre (including Nena, Extrabreit and the sisters Annette and Inga Humpe) have their roots in Hagen.Examples include the Volme- and Rathaus-Galerie, the redesign of Friedrich-Ebert-Platz and the station forecourt (Berliner Platz) as well as the construction of the new town hall on the riverside.[14] Owing to the extensive use of water power along the rivers Ruhr, Lenne, Volme and Ennepe, metal processing played an important role in the region of Hagen in and even before the 15th century.One of the five branches of South Westphalia University of Applied Sciences is located in the city (also: Fachhochschule Südwestfalen (FH SWF)), which offers various engineering programmes.Trades such as printing, brewing, smithing, milling, and many others are represented, not only with static displays, but as living, working operations that visitors may in some cases participate in.The marshalling yard of Hagen-Vorhalle is among Germany's largest, and the central station offers connections to the ICE network of Deutsche Bahn as well as to local and S-Bahn services.