The Second Battle of the Masurian Lakes or Winter Battle of the Masurian Lakes, known in Germany as the Winter Battle in Masuria and in Russia as the Battle of Augustowo, was the northern part of the Central Powers' offensive on the Eastern Front in the winter of 1915 during World War I. The offensive was intended to advance beyond the Vistula River and potentially knock Russia out of the war. It was the last major battle fought on German soil during World War I.