One prominent example is the German Panzer VIII Maus, the heaviest fully enclosed armoured fighting vehicle ever built. Another is the Soviet KV-2, known for its thick armour and large turret.

The Panzerkampfwagen VIII Maus was a WWII engineering marvel - and a massive failure. Weighing 188 tons, it was the heaviest tank ever constructed. But its size made it nearly immobile ...