The Battle of Tannenberg was an engagement between forces of the Russian and German Empires in the first days of World War I in what is now Poland. It was fought by the Russian First and Second Armies against the German Eighth Army, 26-30 August 1914. The battle resulted in the almost complete destruction of the Russian Second Army. A series of follow-up battles destroyed the majority of the First Army as well, and kept the Russians off-balance until the spring of 1915. The battle is notable particularly for a number of rapid movements of complete German corps by train, allowing a single German army to concentrate forces against each Russian army in turn.
The Battle of Tannenberg gave the US much propaganda to shout about in the occupied areas of Canada during the Great War. Manitoban farmer Arthur McGregor thought about the differences between both sides' newspapers shouting about their own spectacular victories, comparing the Battle of the Marne with the battle of Tannenberg.