IS-2 - Iosef Stalin 2 - WW II Russian heavy tank. With 160 mm (6.3 inches) front armor, and a 122 mm main cannon
IS 2 was Soviet Union's answer to German King Tiger. Shells from the 122 mm canon could penetrate front armor of the German Panther.
Explosive shells were very effective against bunkers and dug in guns. IS-2 bunker busting capabilities were used in the last major battle of World War II
in Europe - Battle of Berlin. The tank in the picture was a part of 200,000 strong Polish army fighting alongside the Soviets
on the Eastern Front. Currently in the Polish Armed Forces Museum, in Warsaw, Poland.