The Russian invasion of East Prussia was a military campaign during World War I that resulted in the occupation of the region by Russian forces.
European theatre of World War I Explained
The European theatre of World War I was a major conflict that took place primarily in Europe from 1914 to 1918, involving many European nations and resulting in significant casualties and territorial changes.
Battle of Tannenberg Explained
The Battle of Tannenberg was a decisive World War I conflict in which the German Empire defeated the Russian Empire.