The T-54 and T-55 tanks , were a series of main battle tanks designed in the Soviet Union. The first T-54 prototype appeared in March 1945, just before the end of the Second World War. The T-54 entered full production in 1947 and became the main tank for armored units of the Soviet Army, armies of the Warsaw Pact countries, and others. T-54s and T-55s were involved in many of the world's armed conflicts during the late twentieth century.
The T-54/55 series, eventually became the most-produced tank in history. Estimated production numbers for the series range from 86,000 to 100,000. T-54/55 tanks were replaced by the T-62, T-72, T-64 and T-80 in the Soviet and Russian Armies, but many remain in use by up to 50 other armies worldwide some having received sophisticated retrofitting. Soviet tanks never directly faced their NATO Cold War adversaries in Europe. However, the T-54/55's first appearance in the west in 1960 spurred the United States to develop the M60 tanks.