Question: Who canceled the project for the Landkreuzer P. 1000 Ratte, which would have surpassed the Panzer VIII Maus as being the heaviest fully enclosed armoured fighting vehicle ever built?
Sentence (from "Panzer VIII Maus"): Panzerkampfwagen VIII Maus ("Mouse") was a German World War II super-heavy tank completed in late 1944.
Relevant evidence: Yes