Battle of the Iron Triangle
1974 CE.
Shown on the map at 11.133°, 106.544°.
The Battle of the Iron Triangle took place from 16 May to 20 November 1974, when the People's Army of Vietnam (PAVN) 9th Division captured Rach Bap and An Dien. The Army of the Republic of Vietnam (ARVN) regained the lost towns in a series of costly counterattacks.
Text from the Wikipedia article Battle of the Iron Triangle, licensed CC BY-SA 4.0.