One of the greatest projects implemented during the Soviet era before the World War II, was the construction of the "line of fortified regions on the border of the Soviet Union" or, as these fortifications were called in the Western press, "Stalin Line".
The line was made of dozens of separate so called fortified regions. Each of these regions contained a foundation made of concrete bunkers, observation points and auxiliary structures. During the wartime these foundations were improved by field manning (field fortifications and positions of troops).
Construction of fortifications started in the late 1920-ies and up until 1938 there were 13 fortified regions built during the first stage. In 1939 the second stage of construction began – 8 more fortified regions were built including the fortified region in Kamianets-Podilskyi. The purpose of this line was to protect the strategically important regions of the USSR in case of war and to provide some time for the army to mobilize and dislocate its troops. The fortified regions of the first stage covered the strategically important administrative and industrial regions; the fortified regions of the second stage were practically moved to the border. The Kamianets-Podilskyi fortified region was built during 1938–1941, it consisted of 159 bunkers, was about 100 km long and up to 10 km deep.
The Kamianets-Podilskyi fortified region did not take part in the battles during the opening stages of the World War II as Germans started invasion further up north – in the Volochysk area, and as a result the Kamianets-Podilskyi fortified region’s permanent post was relocated. After the war the fortified "Stalin Line” appeared to serve no military purpose. Bunkers were being used to discharge wastes and defuse landmines, that were laid in the fields during the war.
These days the Stalin Lines can be seen scattered all over the fields of Kamianets-Podilskyi region along the Dniester and Zbruch rivers.