World’s biggest gun ‘Gustav’ built by the Nazis to destroy France that fired 12ft shells before vanishing without trace

NAZIS once built the world's biggest gun that weighed 1,490 tons and fired 12ft shells as they prepared to wreak havoc in France.

Dubbed "Miracle weapon" by the Germans, the Schwerer Gustav railway gun was the largest artillery piece that was deployed in World War Two.

From the ground, the gun looked like a four-storey building - and was 140ft long and 20ft wide.

Just the barrel of the wonder weapon was 100ft long - and could fire two kinds of shells: a 10,584-pound high-explosive shell and a 16,540-pound concrete-piercing shell.

A single shell of the gun was taller than two men, and twice as wide as one.

The gun was so big that hundreds of men were needed just to operate the mammoth machine and fire a single round.

With a calibre of 31 inches, Gustav could hit targets roughly 30 miles away with a force that could destroy enemies to the ground.

The gun was actually transported in five units: the breech ring and block, the barrel split in two halves, the barrel jacket, the cradle, and the trunnions.

The supergun was designed by Krupp - a steel company based in Esses - in 1936 to aid the German invasion of France in May 1940, but was only used against the Soviet Union later in the war,

Back then, the concept of such a mammoth artillery system already existed - with countries like Britain having the 39-ton Tsar Cannon and Germany developing the 47-ton “Big Bertha” in 1914.

Hitler too dreamed of having such an extensive weaponry system that could not only intimidate the enemy - but also smash the targets to the ground.

By the 1930s, the Nazis started drawing up plans for such a weapon that could break through France’s Maginot Line.

This required them to build something that could pierce 22ft of reinforced concrete and at least three feet of solid steel - in other words, a weapon unlike anything the world saw back then.

While the Nazis were able to accomplish such an extensive piece of artillery, they were a bit too late to use the enormous canon in France.

Though the Schwerer Gustav gun was not used to break through the Maginot Line, the Nazis tested the might of the new weapon in 1942.

A team of over 1,000 men reportedly took several weeks to assemble the gun before shipping it off to aid the army during the siege of Sevastopol. 

Schwerer Gustav was first deployed at the Battle of Sevastopol where it blasted through bedrock to destroy an underground munitions depot.

For more than a month, the enormous cannon rained down hell on the besieged Soviet city, firing some 50 giant rounds.

Sevastopol was turned into ruins after its defence line was shattered by the end of the siege - and the Axis powers won a decisive victory.

Soon after that, the Nazis transported the artillery piece to Leningrad (present-day St. Petersburg), but the weapon was never used again.

When the Soviet forces repelled Nazi Germany, the weapon vanished from the military records without leaving a trace.

Most likely, the Germans destroyed their gargantuan gun to prevent it from falling into the hands of the Allies - and was never seen again.