As a result of the largest sabotage and subversive action in the German-occupied Greater Poland, carried out by Polish conspirators from the Home Army, German military depots in the river port were completely destroyed. Several tons of warm clothes from the collections organized on the appeal of Adolf Hitler among the Germans and intended for the Wehrmacht and the Waffen-SS on the eastern front became the target of Poznań saboteurs.

After the end of hostilities in 1939, the area of ​​Greater Poland was incorporated into the Third Reich under the order of Adolf Hitler as part of the Reichsgau Wartheland. The German occupation plans for this land assumed the biological liquidation of the Polish and Jewish population through direct extermination, deportations to the General Government or forced labor in the Reich. The life of Poles in Greater Poland was like living in one big prison. Despite of unusual difficulties, in 1939, Poles started to form underground forces in this area.

The “Bollwerk” action was preceded by an intelligence reconnaissance and the introduction of conspirators to guard companies in warehouses. The pre-war professional non-commissioned officers of the Polish Army were sent there. These activities were also attended by Antoni Gąsiorowski, the head of the local youth gang (the Polish equivalent of Peaky Blinders), known in the area, who conducted the reconnaissance of the area before the action with his people. The decision about the action was issued by General Sikorski.

The diversion was carried out in a perfect way, causing a fire with a properly prepared electric heater and a clock mechanism that caused the explosion. The conspirators in the warehouses prepared special “fire paths” that completed the destruction. The losses resulting from the fire were estimated by the Germans at around 1.5 million marks. The German commission investigating the causes of the fire confirmed that it was caused by a short circuit in the outdated electrical installation.

However, the functionaries of the Poznań Gestapo were of a different opinion. As a result of a thorough investigation, following numerous arrests among the ranks of the Home Army soldiers in 1942, the Germans managed to apprehend most of the participants of the action and reveal its true course. 15 participants were brought before a German court, including the commander Michał Garczyk “Kuba”. 11 of them were hanged and the rest died in German concentration camps. Gąsiorowski did not survive the prison either. During the interrogation, he severely beat up the Gestapo officer interrogating him and died tortured by the guards.

The soldiers of the “Bollwerk” action were commemorated in Poznań with a plaque unveiled 40 years later on February 21, 1982.