The main object of the excursion is a gun battery, that has no analogues in the history of such kind of buildings. It is situated at the bottom of Russkiy island on the closed position and includes two turrets of three - barrels guns dismounted from "Poltava" battle -ship.
The under-turret rooms, shell rooms and powder-magazines are at the depth of 25 metres. The shells of half a tonne could hit the target at 35 km distance.
In one of fort №12's casemates there is a unique fresco icon.