I love the sheer, almost absurd size of the really huge guns. You can't help but go "wtf!?", for instance, when seeing the Pumhart von Steyr's enormous bore coupled to a tiny, tiny breech, in a squat whole that makes it remind me of Fizzgig from
The Dark Crystal! And of course, the Paris Gun. A gun that needs supports merely to remain straight. That's just two of 'em.
I guess the most wonderful thing about them is that, but for their having been made, one would say that they were flights of fancy - very fanciful fancy at that.
Separated at birth: Fizzgig and the Pumhart von Steyr 