World War 2 was the most devastating war in human history. If we forget about the events that ended the war thousands of miles away, Germany, Europe and the rest of the combatants used plenty of conventional weapons to wreck havoc on each other for nearly 6 years.
The above shows Hitler and some generals admiring the massive Gustav Gun. A weapon so large that it was mounted on rails. It fired shells over 30 inches in diameter weighing 7 tons at a range of nearly 30 miles. The main purpose was to utterly destroy the forts of the Maginot Line. Though it was transported and used in Operation Barbarossa.
Unfortunately, it was destroyed by the Germans themselves in order to prevent it’s capture by those damned Commies towards the end of the war in 1945. And while there have been more massively wide guns made, The Gustav remains the largest caliber rifle ever used in war time.
Check out this quick little video regarding some of the famous railroad guns: