28 September — Warsaw surrenders to Germany; Modlin surrenders a day later; the last Polish large operational unit surrenders near Kock 8 days later.
In the autumn of the same year the new tank was tested by the Centre for Armoured Troops Training at Modlin Fortress.
The construction started almost immediately, although Chief Engineer of the French forces Gen. François de Chasseloup-Laubat decided to build the fortress on the northern bank of the river rather than on the islands.
Team Fortress 2 | Boeing B-17 Flying Fortress | Fortress of Louisbourg | Brest Fortress | Akershus Fortress | The Super Dimension Fortress Macross | Peter and Paul Fortress | Niš Fortress | Modlin Fortress | Defense of Brest Fortress | Nehaj Fortress | Modlin | Miracle Fortress | Fortress Saint-Maurice | Fortress of Kaysun | Augsburg Fortress | Antonia Fortress | Warsaw Fortress | Varberg Fortress | ''The Memphis Belle: A Story of a Flying Fortress'' | The Hidden Fortress | Skopje Fortress | Sharpe's Fortress | Salacgrīva fortress | Real Felipe Fortress | Peter and Paul fortress | Osowiec Fortress | Norske Løve Fortress | Morro Castle (fortress) | Modlin Army |
In early July, the division was ordered to the area near Grodno in Poland, where it would form a part of SS-Obergruppenführer Gille's IV.SS-Panzerkorps, covering the approaches to Warsaw near Modlin.