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.
Tanks in the British Army
In 1939, most tanks had maximum armour of 30 mm or less, with guns no heavier than 37–47 mm. Medium tanks of 1939 weighed around 20 tons. Also if the tank's gun was to be used to engage both unarmoured and armoured targets, then it needed to be as large and powerful as possible, making one large gun with an all-round field of fire vital. Also, mounting the gun in a turret ensured that the tank could fire from behind some cover. Hull-mounted guns required that most of the vehicle be exposed to enemy fire. Multiple-turreted or multi-gun designs such as the British A9 Cruiser Mk I slowly became less common.