One of the forts of the former Festung Posen, located in the Old Zoo.

The 19th century Poznań Fortress is one of the best preserved examples of such objects in Europe. Its construction consisted of two stages. The first stage, initiated in the first half of the 19th century, included the training ground fortress - virtually non-existent today. Its remains are the Cathedral Sluice and the Citadel. In the second part of the century military technology was considerably more developed, especially in its artillery aspect. Consequently, the decision was made to build a multiple fort fortress. The fortress works from that period have been mostly preserved until the present day.