If you look at the modern artillery that contemporary armies use today, you wouldn't believe how far they've truly come. Large artillery has existed in some shape or size for centuries. If you looked back to the medieval times, the heavy mortar cannons of their day were huge wooden catapults and trebuchets launching gigantic boulders or flaming tar barrels. With the discovery of gunpowder and the progress of military weaponry, the destructive force has become more menacing, but the devices have gotten gradually smaller. Here we look back at the iconic and infamous milestones in the history of large artillery, there are a few surprises too.

Atomic Annie was an artillery piece built by US that had the capability to fire nuclear ammunition. It was designed and developed during the early 1950s and was used in active service by 1953 in Europe and Korea. The first and only ever test of Atomic Annie was performed at the Nevada Test Site in 1953, it ended with a 15 kt shell being launched 7 miles into the Nevada desert. The launch proved to be the only nuclear shell ever fired with Atomic Annie.

As a result of the successful test, 20 more cannons were commissioned to be built at the cost of $800,000 each. After they were all built, more effective weapons had been developed and were being used, rendering the Atomic Annie obsolete.

2B1 Oka is a self-propelled gun produced during the mid 20th century by the Kirov Plant for the Soviet Union. It had a 420 mm calibre gun with an incredible 20 meter barrel, that allowed the 2B1 Oka to fire a 750kg shell up to 45 km. Whilst it was an extremely powerful weapon, the intricate reloading mechanisms meant it could only be reloaded once every five minutes.

It was constantly being developed until 1960, as the Soviet Union decided to swap the idea of overpowered weapons for tactical and accurate weaponry.

Big Bertha was a heavy siege gun that was used during the First World War, it was created by the famous German armaments manufacturer Krupp. Whilst there were only two Big Bertha models in use at the beginning of World War I, it built a fierce reputation. It was used to destroy various Belgian and French forts, destroying several in just a few days. Big Bertha gained a formidable reputation, even though the forts it destroyed were built in the 1880s and were poorly constructed. Later assaults proved Big Bertha to be fairly ineffective against modern fortifications.

During the course of the war, a total of 12 Big Berthas were eventually built. Several were self destroyed due to faulty ammunition bursting the barrels. At the end of the First World War, two were captured, one was captured by the US and the fate of the other is unknown.

Mons meg has an enigmatic history, the actual origin of the medieval gun is unknown but it is widely thought that it was commissioned by the Duke of Burgundy, who sent it to King James II of Scotland as a gift in 1457.

The cannon had a 510 mm calibre and was apparently one of the many armaments on James IV's The Great Michael, this would've made it the ship with the largest calibre gun in history.

It could only ever be fired between eight and ten times a day due to the heat generated by the powder charge. Mons Meg has been officially retired from active service since the 1540s and has only ever been fired on ceremonial occasions.

The emphatically named Thor was a self propelled siege mortar created by the Germans during the Second World War, as a self propelled mortar it could move around without the use of an additional vehicle. Thor was once the largest ever self-propelled weapon to see service. The ammunition was so colossal that an accompanying crane, a heavy transport trailer and several modified tanks were needed to carry its shells.

Thor was one of the 7 commissioned mortars labelled Gerät 040th by the manufacturer Rheinmetall Borsi. The others were Adam (later named Baldur), Eva (later named Wotan), Odin, Loki, Ziu and Fenrir. The final fate of Thor is not fully known. It is thought that it was captured by Russian forces.

The Great Gustaf was a gargantuan railway siege gun built by the Nazis in the 1940s, it's called a railway siege gun because it actually had to be mounted on a railway to keep it's stability and structural integrity. It was one of two guns of it's kind, it was built in preparation for the second world war. And almost in retaliation of France's construction of the Maginot Line, that stretched across the Franco-German border. The barrel of the Great Gustaf was a formidable 32.48m in length and had a 800mm calibre, which made the Great Gustaf the largest calibre piece of artillery to ever see actual combat at the time.

It was eventually captured by American troops after being used in Operation Barbarossa, it was completely destroyed by the US troops, as a 1,350 tonne railway siege gun couldn't be captured and transported back to US soil.

The Pumhart von Steyr was created all the way back in the early 15th century and is truly a piece of archaic, annihilating artillery. It could fire a 690kg cannonball approximately 600m with the aid of 15kg of gunpowder. It is famous for having the largest calibre of any wrought iron cannon, it has an impressive 800m calibre.

The siege cannon is currently on display in the artillery halls of Heeresgeschichtliches Museum in Vienna.

It might sound like the name of a rubbish pop band but it was actually a relatively ancient cannon commissioned by Tsar Feodor in 1586. It weighed an awesome 39 tonnes, despite being just 5.34 metres in length.

It had a 890 mm calibre, making it the largest cannon ever made for firing stone cannonballs. Even though it's purely a decorative piece, modern research found gunpowder residue in the barrel which confirmed the cannon was fired at least once.

The cannon is covered in raised etchings, the most prominent being a relief of Tsar Feodor Ivanovich on horseback. The cannon is now within the walls of the Kremlin in Moscow.

Designed by Robert Mallet, Mallet's Mortar was a British mortar cannon intended for use during the Crimean War during the middle of the 19th century. The uniqueness of the mortar cannon came from it's ability to be split into numerous sections, making transport easier.

The design was publicly released in 1954 by Robert Mallet and after contacting the then current Prime Minister, Lord Palmerston, the construction of two mortar cannons was commissioned. Testing finally commenced in 1857 and finished in 1858, every test performed was prematurely brought to an end due to mortar damage. Mallet's Mortar had an impressive 910 mm calibre, but had a dismal range of only 1.5 miles with a 2400 pound shell.

It was never used in the Crimean War, the testing model is now kept at the Royal Artillery Base in Woolwich and the the unfired gun is on display at the Royal Armouries Fort Nelson.

Americans truly love their irony, though in name Little David may sound diminutive, it is actually still one of the biggest mortar cannons ever made, with an impressive 914mm calibre. It was originally built by the Americans to test aviation bombs during the second world war but with the inevitable invasion of Japan looming. Little David was converted into a siege mortar for short range warfare. But we all know what course the Second World War took. Before Little David even had a chance to prepare shelling Japanese soil, the US army dropped two atomic bombs in Japan. This meant the end of the war and meant that Little David was only ever used in testing. A relatively short range of 9.7km and terrible accuracy meant the mortar cannon was retired before it saw any real action.

Whilst it holds the bragging rights of being one of the biggest pieces of artillery, it was never proven in combat and will always be a 'what if' weapon.