Battle of Stalingrad
The city was briefly defended by the 1077th Anti-Aircraft Regiment, an all-women's regiment that was actually able to halt an entire German division due to their massive firepower. The Germans eventually swarmed and killed them, but were shocked to discover that this whole time they were being held back by young women that seemed fresh out of high school. In the battle, the NKVD organized  "Workers' militias" who were often sent into battle without rifles.