The German-Soviet border, running between Stary Dzików and Oleszyce, was heavily fortified between 1939-1941 in anticipation of an inevitable clash between the temporary allies. Near Oleszyce, five concrete bunkers are located, with additional ones spread near Dachnów. All these bunkers formed a screen for Lubaczów. They were equipped with machine guns, and only occasionally had anti-tank guns to resist expected tank assaults. Most are located close to main roads, indicating that their primary purpose was to block these routes. They are freely accessible, but caution is advised when exploring due to their location in damp terrain and potential flooding.