Let's have a thread about 19th/20th century battles were largely outnumbered, but held out for long or even won.

I will start with battle of Wizna. On 7th of september 1939 Wehrmacht's 3rd army, under the command of Heinz Guderian reached a fortified line of defense at Wizna (which was around 35km/22mi away from the borders with East Prussia). Number of Polish troops that took part in the battle are thought to be between 350-720, with 6 76mm guns, 42 MGs and 2 anti-tank rifles. The Germans on the other hand where 42000 men, with 350 tanks, 657 mortars and howitzers and aerial support from Luftwaffe.

Poles held their position for 3 days, until the last remaining bunker ran out of ammunition and the commander ordered his men to surrender, while he killed himself with a grenade (before he sworn that he will hold the ground, or die).

Poles managed to hold back the Germans for 3 days, which postponed the encirclement of Independent Operational Group Narew.