Siege of Fort Alexandrovskogo
1870 CE.
Shown on the map at 44.517°, 50.267°.
The siege of Alexandrovsky fort (Russian: Осада Александровского форта) was an unsuccessful attempt by the Kazakh rebels to take the only fortified fort in the region, the expedition arrived in time and saved the garrison from death.
Text from the Wikipedia article Siege of Alexandrovsky fort, licensed CC BY-SA 4.0.