Battle of Częstochowa
1939 CE.
Shown on the map at 50.817°, 19.138°.
The Battle of Częstochowa was one of the first battles of the Invasion of Poland during World War II. It took place on September 1–3, 1939.
Text from the Wikipedia article Battle of Częstochowa (1939), licensed CC BY-SA 4.0.