The Battle of Masurian Lakes was a significant military engagement during World War I, occurring from February 7 to February 22, 1915. It involved the forces of the German Empire and the Russian Empire in the Masurian Lakes region of present-day Poland. The battle aimed to push back Russian troops and secure German control over East Prussia. The battle followed the earlier Battle of Tannenberg, where the Germans had already achieved a decisive victory. In this engagement, the Germans successfully encircled and defeated Russian forces, leading to heavy casualties and a retreat by the Russians. The outcome solidified German dominance in the Eastern Front for a time.