Abstract This paper aims to present architectural and educational features of historic military architectural structures in Poznań. The issues treated herein include the preservation of forts today and the resulting opportunities as well as difficulties in the use thereof for new functions reflecting the contemporary needs of a city. The paper provides three detailed examples of Polish and international military architecture refurbishments. The Graf Kirchbach Fort III in Poznań was chosen for the needs of the paper. The research material was developed on the basis of literature research, fort III survey and information obtained from Poznańskie Towarzystwo Przyjaciół Fortyfikacji [Poznań Friends of Fortifications Association]. The knowledge and research contained herein demonstrate the potential of post-fortification architecture, its cultural value as well as conversion opportunities in accordance with sustainable design objectives.