The Landkreuzer P 1500 Monster was a German pre-prototype super-heavy artillery designed during World War II, representing the apex of the German extreme artillery designs.
The Landkreuzer P. 1500 Monster was to be 42 m (138 ft) long, weighing 1500 tonnes, with a 250 mm hull front armor, four MAN U-boat (submarine) marine diesel engines, and an operating crew of over 100 men.
The main armament was to be an 800 mm Dora/Schwerer Gustav K (E) railway gun, and with a secondary armament of two 150 mm sFH 18/1 L/30 howitzers and multiple 15 mmMG 151/15 autocannons. The main armament could have been mounted without a rotating turret, making the vehicle a self-propelled gun rather than a tank. Such a configuration would have allowed the P. 1500 to operate in a similar manner to the original 800mm railroad gun and Karl 600mm self-propelled mortars, launching shells without engaging the enemy with direct fire.