Imagine a land vehicle 35 meters long, 11 meters high, and weighing 1,000 tons, carrying a battleship turret, eight anti-aircraft guns, an infirmary, and a garage for two BMW scout motorcycles. This episode digs into the Landkreuzer P1000 Ratte, pitched to Hitler in June 1942 by Krupp submarine engineer Edward Grote and assigned official project numbers by the German high command. We trace how a 1941 study of Soviet heavy tanks spawned the 188-ton Maus and then spiraled into a proposal more than five times heavier.

The Ratte would have needed roughly 16,000 horsepower from marine diesel engines, six treads paired into two 3.6-meter-wide tracks, and U-boat snorkels for fording rivers. The square-cube law meant it would have sheared through topsoil, it could not fit through any European rail tunnel, and its 28-centimeter naval guns required a ...