Wierzchowiny massacre
1945 CE.
Shown on the map at 51.031°, 23.414°.
The Wierzchowiny massacre was a massacre in the town of Wierzchowiny perpetrated by the National Armed Forces on 6 June 1945 led by Mieczysław Pazderski, also called "Szary" (Grey).
Text from the Wikipedia article Wierzchowiny massacre, licensed CC BY-SA 4.0.