A historic military bunker complex located near the village of Wizna in northeastern Poland. The site is a key part of the Battle of Wizna (September 7–10, 1939), where a small Polish force held a fortified line against a vastly larger German invasion force during the opening stages of World War II. The surviving bunkers, part of the Polish Border Protection Corps fortifications, are a poignant symbol of the Polish defense and are now a recognized war memorial.
The bunkers were constructed as part of Poland's pre-war defensive preparations along its western border. They were built into the natural terrain and designed to provide cover for infantry and anti-tank weapons. During the battle, approximately 350–720 Polish soldiers defended this section of the line against over 40,000 German troops, inflicting significant casualties and delaying the advance for three days. The fierce resistance at Wizna became a notable episode of the Invasion of Poland.
Today, several of the reinforced concrete bunkers remain intact along the Narew River valley. The site is maintained as a historical monument and attracts military history enthusiasts and visitors commemorating the events of 1939. The area's landscape and the surviving fortifications offer a tangible connection to this early and dramatic confrontation of World War II.