The Home Army Museum is one of the few museums in Poland devoted entirely to the history of the Polish Underground State and the Home Army. Its collection comprises approximately 20,000 items, largely donated by Home Army veterans and their families. Unique items include the first report written by Captain Witold Pilecki after his escape from Auschwitz, the diary of Major Henryk Dobrzański "Hubal" Dobrzański's Polish Army Detachment, and Tadeusz Kantor's painting "The September Defeat". Also noteworthy are a 14-meter replica of a german V2 rocket, a mock-up of a Vickers tank, a fragment of a Halifax aircraft fuselage, and extensive collections of uniforms, arms, and military insignia. The main exhibition, titled "The Polish Underground State and Its Armed Forces," attractively presents the origins and development of the underground state structures and the Home Army during World War II.