The Defence of the Polish Post Office in Danzig (Gdansk) was one of the first acts of World War II in Europe, as part of the Invasion of Poland.
On September 1, 1939, Polish personnel defended the building for some 15 hours against assaults by the SS Heimwehr Danzig (SS Danzig Home Defence), local SA formations and special units of Danzig police.
All but four of the defenders, who were able to escape from the building during the surrender, were sentenced to death by a German court martial as illegal combatants on October 5, 1939, and executed.