Paknam Incident
1893 CE.
Shown on the map at 13.538°, 100.584°.
The Paknam Incident was a military engagement fought during the Franco-Siamese crisis in July 1893. While sailing off Paknam on Siam's Chao Phraya River, three French ships violated Siamese territory and a Siamese fort and a force of gunboats fired warning shots. In the ensuing battle, France won and blockaded Bangkok, which ended the war.
Text from the Wikipedia article Paknam incident, licensed CC BY-SA 4.0.