In late August 1914, at Tannenberg, in today's Poland, took place one of the most momentous battles of World War I between Germany and Russia. The fate of the entire eastern front would be decided in this small town, where the German General Paul von Hindenburg met with Grand Duke Nicholas, uncle of Tsar Nicholas II.
The Eighth German army had fewer than 250,000 men, while the Grand Duke had two armies which in total amounted to 500,000 troops, but the rivalry and lack of support among the generals who commanded each of the Russian armies, would be decisive causes of defeat.
Tannenberg meant a tremendous psychological blow to the Tsarist Russia, from which he never recovered, encouraging shortly after the Bolshevik Revolution of 1917.