The fourth fortress is the most famous of the forts in Grodno Castle, and this is explained by the fact that it has been perfectly preserved to this day. The work was carried out for seven years and was completed in 1888. The fort has a dry trench, protected from the outside by an anti-cliff stone wall on the faces and wings, and it also includes a number of shelters and places for sleeping for the soldiers who took up the operations of defending the city at the time.