Following the November Uprising of 1830, imperial Russia built this pentagonal brick fortress to enforce its power over Warsaw. It covers 36 hectares and, at the time of research, much of it was a construction site for the future Polish History Museum (http://muzhp.pl) and relocated Polish Army Museum set to be completed around 2021.
The sections you can visit are the Katyn Museum; the eastern gate Brama Straceń; and the Museum of the X Pavilion of the Warsaw Citadel.