Cold War, Modern Day

Switzerland’s Centi Bunkers – Centurion Turrets in the Swiss Mountains

When you think of Switzerland, you probably imagine stunning views, skiing, or perhaps their banks, watches and delicious chocolate. Switzerland is not often associated with military activities, especially considering it is famously neutral.

So you might be very surprised to hear that Switzerland is actually one of the most militarised nations on the planet. Okay, they aren’t militarised in the typical sense, with a massive army, tanks and aircraft etc., but despite their friendly associations, they have taken the threat of war very seriously.

Switzerland’s power comes not from in its army, but in its defenses. The entire country has been engineered to make life for any invader as difficult as possible. One of the most intriguing creations for us, is their use of bunkers created to house Centurion turrets – known as Centi Bunkers.


The Fortress that is Switzerland

During and after Second World War, Switzerland was acutely aware of the threat of being invaded. The subsequent Cold War meant that this was a very real possibility, should conflict spark between the USSR and the West.

The mountainous terrain of the country provided a natural defense for Switzerland, as they limited the movement options for an invader.Switzerland built upon this by lining the canyons and valleys between the mountains with bunkers, fortifications, guns, tunnel networks and supply dumps.

Switzerland Turret shed.
“I am just a shed – keep walking”. Image by Magletsch CC BY-SA 3.0

These defenses utilised the natural hills, rivers, forests, valleys and chokepoints to bolster their effectiveness. Areas that were particular vulnerable, or were the most likely location of an invasion, were reinforced.

Any advantageous positions were capitalised on.

Switzerland also protected its civilians against these threats – including nuclear ones – with a 1962 law mandating that each citizen is entitled to one square meter of space inside a shelter.

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In addition, any new dwellings built after this date must have a fallout shelter.

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As a result of this, Switzerland has the highest proportion of underground shelters for its population of any nation in the world. Using 2022 figures, there are around 370,000 shelters in Switzerland, for a population of 8.7 million.

Switzerland bunkers in cliff face.
Yes, there are firing positions in this image! Image by Paebi CC BY-SA 4.0.

There is enough room in these shelters to house 110% of Switzerland’s citizens – that’s right, they literally have enough room to house more than their entire population.

So with that being said, we can start to see why Switzerland shoved Centurion turrets inside bunkers.

Building the Centi Bunkers

The idea first arose in the 1980s. The Swiss were looking to retire their fleet of 226 Centurions, which they had acquired from South Africa in the 1950s.

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By this time they were showing their age, and Switzerland wasn’t interested in a costly upgrade program to keep these old machines sharp. But they also didn’t want to simply scrap them – their 105 mm guns were still very capable.

So there were some discussions on what to do with them, which considered cost, time, efficiency, etc. In the end, they settled on using the turrets as static defenses.

Centi Bunker turret.
The Centurion turret inside a Centi bunker. Note the additional armor welded on the front of the turret. Image by Emilfrey CC BY-SA 4.0.

This was certainly not a new solution, with many countries doing the same decades before.

However, rather than simple place the turret on a bearing race and leave it be, they were going to be an integral part of the bunker. The turrets would be placed in strategic locations, and equipped with optics to enable firing at night and even in bad weather.

Some additional armor would be added to the front of the turret, and the bunker that housed it would be proof against guns up to 203 mm in caliber.

Centi Bunker turret stowed.
The turret in the stowed position. The indent on the right hides the gun from view. Image by Kecko CC BY 2.0

The first Centurion turret bunker, known a “Centi bunker”, was completed in 1990. Their were officially designated as an M-0907 Bunker. Initial plans detailed the construction of 100 Centi bunkers, but the Soviet Union collapsed during the project, so their need greatly reduced.

As a result only 20 Centi bunkers were built in the end, for a total of 400,000 francs each.

Their construction was relatively straight forward – this is arguably the most experienced bunker-building nation in the world after all – but the turrets were much harder to move.

Centurion Turret Transporter, Switzerland.
The Centi bunker turret transporter. It’s a modified Centurion used to help build the bunkers. Image by Massimo Foti.

Rather than truck them up, the Swiss converted a Centurion into a special “turret carrier”. Large welded structures were attached to the front and back of the Centurion’s hull, which added huge, half-meter wide, hydraulic outrigger jacks onto each corner.

The four corner jacks were capable of lifting the entire tank off the ground. In addition, a hydraulically operated crane was attached to the rear.

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All in the contraption weighed 63 tons, and while mobility reduced, this was acceptable because it was no longer a combat vehicle.

Centurion Turret Transporter in Swiss museum.
These huge jacks were capable of lifting the entire vehicle off the ground. Image by Massimo Foti.

With these modifications, this vehicle would carry the Centurion turrets to the remote locations of the planned Centi bunkers.

The turret would sit in its normal place on the hull during transport, and would then be craned off by the crane at the rear.

Once the turret was placed onto its mount, the rest of the bunker would be built around it, and it would be rigged up to the facility’s electrical systems for communications and power.

It appears that the 105 mm gun would be transported up separately, and fitted into the turret once it was in place.

Centi Bunker turret Transporter in action.
The Centi Bunker turret transporter in action. Note the outrigger jacks keeping the tank level. The crane is about to lift the turret off.

Inside a Centi Bunker

Supporting the turret was a small complex within the bunker. There was, of course, the turret’s firing room, but there was also shelter for the bunker’s crew, an ammunition room, a ventilation system and a power supply.

The turret was accessed from a room underneath via a ladder, which rotated with the turret. The crew stood on a metal floor that function like a typical turret basket, and, when in use, it functioned virtually the same as a normal tank turret.

Inside the Centi Bunker, below the turret.
The access ladder to a Centi bunker turret. Crews entered from underneath, rather than on top like a tank. Image by Kecko CC BY 2.0.

At the front of the firing room was a small embrasure (opening) through which the gun could fire, so the turret was limited in traverse.

However it presented a much smaller target for enemy guns. The openings could be covered when not in action, and the fronts were painted to resemble stone to blend them in with their surroundings.

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The gun barrel could be hidden from view thanks to an indentation on one side of the embrasure.

Centi Bunker turret inside.
Inside a Centi bunker turret. Image by Kecko CC BY 2.0

The turret would simply need to be turned to the correct position to “stow” it.

Inside the turret was a quickly accessible ammunition supply, a basket to catch spent casings, and a thermal imager. This last feature was particularly important, as it allowed the turrets to operate in all conditions, day or night.


We mentioned earlier that the collapse of the Soviet Union reduced the quantity of Centi bunkers from 100 to just 20. This major event also impacted the longevity of the bunkers, because the threat of a Soviet invasion had reduced massively.

Centurion bunker from the outside.
Here you can see the camoflaged panels that cover the opening. From a distance, it would be difficult to spot this position. Image by Kecko CC BY 2.0.

These fascilities required a large number of crews to function, and this cost was no longer justified. As a result, Switzerland began decommissioning them after the turn of the century, and they were out of service by 2003.

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Today, some of the Centi bunkers have been converted into museums and can be toured by the public. If you’re in the area, keep an eye out, that pile of rocks may be an old Centi bunker!