Battle of Łomianki
1939 CE.
Shown on the map at 52.336°, 20.894°.
The Battle of Łomianki was a part of the opening campaign of World War II during the 1939 German invasion of Poland, fought between Polish and German forces. It was a failed counter-offensive attempt by the Polish forces.
Text from the Wikipedia article Battle of Łomianki, licensed CC BY-SA 4.0.