Established in Hagen in 1902 as the successor to the Folkwang
Museum, the Osthaus Museum Hagen consciously deals with
contemporary art in the tradition which is today called “Hagener
Impuls”. In the Henry van de Velde art nouveau rooms and addional rooms, classic
modern works and international contemporary art are displayed. This is supplemented
by a diverse programme of changing special exhibitions as well as an active art
education in the “Junges Museum” (young museum).

 
A short english summary about the museum
  here.