Lisbon Massacre
1506 CE.
Shown on the map at 38.708°, -9.139°.
On 19 April 1506, a crowd of churchgoers in Lisbon attacked and killed several people in the congregation whom they suspected were Jews. The violence escalated into a city-wide, antisemitic riot that killed between 500 and 4,000 "New Christians" (Cristãos-Novos), the name for Jews who had been forcibly converted to Christianity.
Text from the Wikipedia article Lisbon massacre, licensed CC BY-SA 4.0.