
The Landkreuzer, as its name suggests was meant to be a sort of warship on land. Weighing over 1000 tonnes, it would have been over 35mtrs long and powered by two u-boat engines.
Here's an artists impression of what it might have looked like, together with examples of other monster tanks, some of which actually made an appearance in steel: Then there was the 'Maus', a modest 188 tons, and only 33 ft long, by comparison. Two were made..well one and a half, since one prototype was minus a turret. It had a 128mm cannon, and armour in excess of 200mm
(8in) practically throughout. Then there was the British Tortoise A39, at over 80tons, and sporting a 94mm gun, 9 were built. Here's a working survivor at Bovington. Just listen to that mean old Rolls Royce motor..
Then the soviets but what looks like a modifies sub with the T-35: More monsters lurking out there..