During the invasion of Poland in WW2, 720 Poles defended their position against 40,000 Germans, stopping their advance for 3 days.
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 the 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 defense 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.
Because the battle consisted of a small force holding a piece of fortified territory against a vastly larger invasion for three days at great cost before being annihilated, Wizna is sometimes referred to as the "Polish Thermopylae". One of the symbols of the battle is Captain W?adys?aw Raginis, the commanding officer of the Polish force, 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.