Masurian Lakes
Masurian Lakes, a group of lakes in northeastern Poland. The largest lakes are Sniardwy (47 square miles [122 km2]) and Mamty (40 square miles [104 km2]). The Germans twice defeated the Russians here during World War I—in September, 1914, and February, 1915. The lakes are in the region of Masuria, part of the German province of East Prussia until the end of World War II.