Soviet (USSR) Armor in WWII.
1939-1945

Prior to the outbreak of WWII, the USSR possessed some 20,000 tanks. This was more than all the tanks in foreign armies combined. The majority of these tanks were either the light infantry tank (T-26) or the light cavalry tank (BT-series, BT-5, BT-7). Medium tanks included the older T-28 and the heavy tank T-35 was in service with some 65 on hand. In 1939, the Soviet Army began a program of modernizing their tank designs and by 1941 were producing the T-34 and KV-1 series tanks that would escalate tank development to previously unforeseen limits.