When it was built, the Big Bertha was the largest mobile artillery piece in the world. The 16.5 inch howitzer was used by the German armies to smash their way through Belgium and into France. Germany built and used a dozen separate Big Berthas in the war.
Each Big Bertha had an effective range of six miles and would fire a nearly eighteen hundred pound projectile. You can imagine the sheer devastating that a single round of the Big Bertha would cause upon impact.