Battle of the Drina
The Battle of the Drina (, ) was fought between the Serbian and Austro-Hungarian armies in September 1914, during World War I. After a first failed invasion, the Austro-Hungarians engaged in a significant offensive over the Drina river at the western Serbian border, resulting in numerous skirmishes (the "Battle of Mačkov Kamen" and the Battle of Gučevo being the heaviest ones). The Serbian Army was forced to end their offensive into Austrian Syrmia, and later regrouped to fight in the subsequent Battle of Kolubara. The Battle of the Drina River is considered one of the bloodiest battle of the first world war. Two Austrian corps sustained almost 30,000 casualties and one Serbian division suffered 6,000 casualties.