Clash at Habersbirk
1938 CE.
Shown on the map at 50.183°, 12.550°.
The Clash at Habersbirk (Czech: Habartov) was the first armed confrontation between the Czechoslovak gendarmerie and the Sudeten Germans. It is sometimes marked as the first battle of the Second World War.
Text from the Wikipedia article Clash at Habersbirk, licensed CC BY-SA 4.0.