Schwerer Gustav or Dora the German 80 cm railway gun

Schwerer Gustav, Wiki

Where is Schwerer Gustav (an 800 mm German railway gun) now? - Quora

The Nazis' Schwerer Gustav Railway Gun, The Biggest Gun Ever Built

Weapons Of Great Wars - Schwerer Gustav was the name of a German 80 cm railway gun. It was the largest-calibre rifled weapon ever used in combat, the heaviest mobile artillery piece

Schwerer Gustav: The World's Biggest Gun Ever Built

This Is The Largest Gun Ever Used In Battle

Big Shots – History's Largest Cannons, Mortars and Super Guns

What is the heaviest shell that can be fired from an artillery piece (not including ballistic missiles or rockets)? - Quora

The Heavy Gustav, Hitler and generals inspecting the largest caliber rifled weapon ever used in combat, 1941 - Rare Historical Photos

Tankies! Dora (Schwerer Gustav) and Karl-Gerat by xSamiamrg7x on DeviantArt