oesterlen's father was the chief engineer of a turbine factory in heidenheim. his family left the town for berlin during world war i. from berlin they moved again to hanover after his father was appointed professor of turbine technology at the local technical college. the foundations to oesterlen's training in architecture began here. he regularly visited exhibitions at the kestnergesellschaft. he attended evening classes in freehand drawing at the school of applied arts. as a young man he worked in some unorthodox places. for instance, after completing high school he worked, as part of his practical requirements, at the construction site of the oder-dam as a carpenter. he was a great observer and absorbed much by merely going from place to place. before he began a formal training as an architect he was already a “student” of architecture. the strict objectivity of the bauhaus building in dessau, which oesterlen visited in the years before he started his architectural degree, made a lasting impression on him.