Brescia Explosion
1769 CE.
Shown on the map at 45.537°, 10.213°.
The Brescia explosion occurred in 1769 in Brescia (now part of Italy) when a large store of gunpowder exploded after a lightning strike, causing extensive destruction and many deaths. Claims that as many as 6,000 people died in the explosion (which may be an exaggeration) place the event high on lists of accidents and disasters by death toll.
Text from the Wikipedia article Brescia explosion, licensed CC BY-SA 4.0.