Panzer VIII Maus
Panzerkampfwagen VIII Maus ("Mouse") was a German World War II super-heavy tank completed in late 1944. It is the heaviest fully enclosed armoured fighting vehicle ever built. Five were ordered, but only two hulls and one turret were completed before the testing grounds were captured by advancing Soviet military forces.
Heavy tank
The immediate post-war period saw the final fielding of heavy tanks, including the US M103 heavy tank, the British FV214 Conqueror, and the French ARL 44 (in very limited numbers for the ARL 44), all in response to the Soviet heavy tanks of the period. The largest tank guns were approaching maximum calibre whose shell could still be handled by the crew, even using awkward two-part ammunition (separate projectile and propellant case, similar to battleship guns), which greatly slowed their rate of fire. Thanks to improved shell designs and fire control technology improving accuracy, postwar medium tanks were catching up to heavy tanks in firepower. The tactical value of heavy tanks thus declined to the point that no new designs were fielded; the heavily armed mediums came to be known as the main battle tank (MBT). Doctrine held that less expensive self-propelled artillery could serve in the infantry support role. The weight of MBTs quickly increased during the Cold War, and most third generation MBTs including the M1 Abrams, Challenger 2, Leopard 2, Merkava, Arjun MBT, and Type 99 have weights similar to those of 1950s heavy tanks.