The Heavy Gustav, a colossal 800mm caliber railway gun, stands as one of the most terrifying and awe-inspiring weapons ever ...

The German Heavy Gustav was the largest gun ever built. It was more than 150 feet long, 40 feet tall and weighed almost 1,500 tons. The steel giant Krupp A.G. made only two, and neither worked well.

The German Heavy Gustav was the largest gun ever built. It was more than 150 feet long, 40 feet tall and weighed almost 1,500 tons. The steel giant Krupp A.G. made only two, and neither worked well.

Gustav cost an estimated 10 million German Marks to build, was used twice, and fired less than 100 rounds. While it was the biggest gun used in combat, it was not the biggest gun ever built.