This day, 27 September, commemorates the phenomenon that was the Polish Underground State during World War II and the people who devoted, and in many instances gave their lives to the continuation of the pre-war Republic of Poland—and its institutions—that waged an armed struggle against the country's occupying powers: Nazi Germany and the Soviet Union.
The Polish Underground State is a collective term for the underground resistance organizations in Poland, both military and civilian, that remained loyal to the Polish Government in Exile in London during World War II.	Flag of the Armia Krajowa

 

The Polish Underground State which functioned under the German occupation in the Second World War was a unique phenomenon in the history of European resistance movements.

 

Polish historian Stanisław Salmonowicz defined the Polish Underground State as a "collection of state-legal, organizational and citizenship structures, which were to ensure constitutional continuation of Polish statehood on its own territory". Salmonowicz added, "This constitutional continuity, real performance of the state's functions on its past territory and the loyalty of a great majority of Polish society were the most significants elements of its existence.

 

The Underground State traces its origins to the Służba Zwycięstwu Polski (Service for Poland's Victory) organization, which was founded in September 1939.