The Battle of Wizna was fought between September 7 and September 10, 1939, between the forces of Poland and Germany during the initial stages of invasion of Poland. According to Polish historian Leszek Moczulski, between 350 and 720 Poles defended a fortified line for three days against more than 40,000 Germans. Although defeat was inevitable, the Polish defence stalled the attacking forces for three days and postponed the encirclement of Independent Operational Group Narew fighting nearby. Eventually the tanks broke through the Polish line and German engineers eliminated all the bunkers one by one. The last bunker surrendered around midday on September 10.

One of the symbols of the battle is Captain Władysław Raginis, the commanding officer of the Polish garrison, who swore to hold his position as long as he was alive. When the last two bunkers under his command ran out of ammunition, he ordered his men to surrender their arms and committed suicide by throwing himself on a live grenade.

Seweryn Biegański, who was the last to leave the shelter, describes the moment;

"The captain looked at me warmly and softly urged me to leave. When I was at the exit, I was hit on my back with strong gust and I heard an explosion."

In his diaries, General Heinz Guderian noted that 900 German soldiers were killed in action, although that number is probably a low estimate. It is certain, however, that the Wehrmacht lost at least 10 tanks and several other AFVs in the struggle.

When the Red Army entered Wizna, the Soviet authorities ordered the bodies to be dug up and moved next to the Łomża - Białystok road, where an obelisk stands today.

The inscription on the monument tablet says;

'Przechodniu, powiedz Ojczyźnie, żeśmy walczyli do końca, spełniając swój obowiązek',

which translates into English as:

'Passerby, tell the Fatherland that we fought to the end, fulfilling our duty.'

Sources: https://en.wikipedia.org/wiki/Battle_of_Wizna

https://en.wikipedia.org/wiki/W%C5%82adys%C5%82aw_Raginis

https://www.warhistoryonline.com/instant-articles/battle-of-wizna.html

The band Sabaton also wrote a song about the battle: https://www.youtube.com/watch?v=4_F6AIhWAiY