Tiger I is a German heavy tank developed in 1942 and used in World War II. It was designed in an effort to counter the unexpectedly impressive Soviet armor encountered in the initial months of the Axis invasion of the Soviet Union, particularly the T-34 and the KV-1. The Tiger I design was Nazi Germany's first heavy tank, mounting the 88 mm gun. During the course of the war, the Tiger I saw combat on all German battlefronts.