During the interwar era of the Free City of Danzig, the autonomous city state had two post offices - one municipal, and one run by the Polish government. As an extraterritorial property of Poland, the Polish Post Office was a bit like an embassy, and surreptitiously served as the centre of the Polish government’s intelligence gathering services in the demilitarised zone of predominantly German Gdańsk! As hostilities between the two countries intensified, the Poles began to stock arms inside the building and train its employees to become a sort of civilian military unit if attacked. 

That moment infamously came on September 1st, 1939, as the Nazi Battleship the Schleswig-Holstein shelled Westerplatte, and the SS simultaneously laid siege to this large brick building in the northern part of the Old Town, inside which 50-some heavily armed postal workers hunkered down. After a brave 17-hour struggle, the details of which are gory indeed, those that were still alive surrendered. After their capture, the 38 survivors were tortured and eventually executed by firing squad on October 5th. A truly impressive stainless steel monument outside the Post Office honours their sacrifice, which has become one of the most romanticised tales of heroism in Polish history. 

After its nearly total destruction, the Polish Post Office in Gdańsk was rebuilt after the war, and is today not only a functioning post office, but also a small, compelling branch of the Museum of Gdańsk dedicated to the events of September 1, 1939, as well as local postal history from the 18th century to the outbreak of WWII. If you can’t get into the WWII Museum, this is a worthwhile, if much less ambitious back-up option.