Soviet Nuclear Bunkers in the Czech Republic

History – In brief

After the end of WWII and the collapse of the Third Reich, the territory now belonging to the Czech Republic fell on the Soviet side of the Iron Curtain. Together with today’s Slovakia, it formed the now disappeared unitary state of Czechoslovakia. Despite laying right on the border with the West – including Bavaria, which was part of West Germany and NATO – communist Czechoslovakia enjoyed a relative autonomy from the USSR, until the announced liberally-oriented reforms of the local communist leader Dubcek in the spring of 1968 triggered a violent reaction by the Soviet leader of the time, Leonid Brezhnev (see here). About 250’000 troops from the Warsaw Pact, including the USSR, landed in the Country. As a result, the Soviets established a more hardcore and USSR-compliant local communist regime, and largely increased their military presence.

Similar to the German Democratic Republic (see here for instance), Hungary (see here) or Poland (see here), since then also in Czechoslovakia the local national Army was flanked by a significant contingent of Soviet troops, who left only after the entire Soviet-fueled communist empire started to crumble, at the beginning of the 1990s.

Consequently, for the last two decades of the Cold War, Czechoslovakia was a highly militarized country similar to other ones in the Warsaw Pact (see here). Its geographical position on the border with the West meant it received supply for a high-technology anti-aircraft barrier (see here). Two major airbases in Czechoslovakia were taken over for use by the Soviets and strongly potentiated (see here).

Soviet Nuclear Depots in Czechoslovakia

Beside conventional forces, also nuclear warheads were part of the arsenal deployed in this Country. Where in the late 1960s Soviet strategic nuclear forces were already mostly based on submarine-launched missiles and ICBMs ground-launched from within the USSR’s borders, tactical forces were forward-deployed to satellite countries, to be readily operative in case of war in Europe. Missile systems like the SCUD, Luna (NATO: Frog) and Tochka (NATO: Scarab) were deployed to the Warsaw Pact, supplying either the local Armies or the Soviet forces on site. Typically armed with conventional warheads, these systems were compatible with nuclear warheads too, making them more versatile, and of great use in case of a war against NATO forces in central and western Europe (see here).

Irrespective of their employment by a local national Army or a Soviet missile force, nuclear warheads were kept separated from the rest of the missile system for security, and invariably under strict and exclusive Soviet control. Bunker sites were purpose built in all components of the Warsaw Pact for storing nuclear warheads – see page 46 of this CIA document, showing with some accuracy the location of the corresponding bases.

Granit– and Basalt-type bunkers were typically prepared on airfields or artillery bases, for short-term storage of soon-to-be-launched nuclear weapons. Instead, top-security Monolith-type bunkers (the triangles on the map in the CIA document) were intended for long-term storage of nuclear ordnance.

Monolith-type bunkers were built by local companies on a standard design in the Soviet military inventory, and were implemented in satellite Countries in the late 1960s. Czechoslovakia received three such sites, which took the names Javor 50, by the town of Bílina, Javor 51, close to Míšov, and Javor 52, close to the town of Bělá pod Bezdězem. All three locations are in the north-western regions of today’s Czech Republic.

The Soviet military started withdrawing the nuclear warheads from satellite Countries in 1989, months before the collapse of the wall in Berlin. As for Czechoslovakia, by 1990 all nuclear forces had been moved back to the USSR. Following the end of the Cold War, Monolith-bunkers – similar to most of the colossal inventory of forward-deployed military installations formerly set up by the Soviet Union – were declared surplus by the Countries where they had been implemented.

These primary relics of the Cold War have known since then different destinies. Some of them have been hastily demolished, and together with their associated fragments of recent history, they have almost completely disappeared into oblivion. Luckily, a few are currently still in private hands, and still in existence (see here and here) – specimens of recent military technology, and a vivid memento from recent history, when the map of Europe looked very different from now. Two can be visited, of which one is Javor 51, in the Czech Republic, the main topic of this post. This has been turned into the ‘Atom Museum’, which has the distinction of being the only Monolith-type site in the world offering visits on a regular schedule (the other open site is Podborsko, in Poland, covered here, which is open by appointment).

Also displayed in the following are some pictures of the now inaccessible site Javor 52 in former Czechoslovakia. Photographs were taken in 2020 (Javor 52) and 2022 (Javor 51).

Sights

Javor 51 – The Atom Museum, Míšov

An exceptionally well preserved and high-profile witness of the Cold War, the nuclear depot Javor 51 is a good example of a Monolith-type installation. These bases were centered around two identical semi-interred bunkers for nuclear warheads.

When starting a visit, you will soon make your way to the unloading platform of bunker Nr.1. The shape of the metal canopy, and the small control booth with glass windows overlooking the platform are pretty unique to this site. The metal wall fencing the unloading area is still in its camo coat outside, and greenish paint inside. Caution writings in Russian are still clearly visible. Concrete slabs clearly bear the date of manufacture – 1968. This site was reportedly activated on the 26th of December, 1968.

Even the lamps look original. Some of the – likely – tons of material left by the Soviets on the premises of this site has been put on display ahead of the massive bunker door.

The opening mechanism of the latter is a nice work of mechanics. Four plugs actually lock or unlock the door. They can be moved by means of a manual crank, or likely in the past via an electric mechanism (some wiring is still visible). The thickness of the doors is really impressive (look for the cap of my wide lens on the ground in a picture below for comparison!).

Each bunker had two ground-level entrances to the opposite ends, each with two blast-proof doors in a sequence. Warheads were transported by truck, unloaded beside the entrance of one of the two bunkers, and carried inside through the two doors, which constituted an air-tight airlock.

Today, you can see the inside main hall of the bunkers from the outside during a visit. This was likely not the case in the days of operation. The opening procedure required a request signal to travel all the way to Moscow, and a trigger signal traveling in the opposite direction. Once past the first (external) door with the warhead trolley, that door was shut, and the procedure was repeated for the second door, giving access to the inside of the bunker.

A security trigger told Moscow when the door was open. It can still be seen hanging from top of the door frame.

Once inside, you find yourself on a suspended concrete platform. The warhead trolley had to be lowered via a crane – still in place – to the bottom of the cellar ahead, i.e. to the underground level. The stairs now greatly facilitating visitor’s motion around the bunker were not in place back then, and descending to the underground level for the technicians was via a hatch in the floor of the suspended platform, and a ladder close to the side wall.

On the platform, an original Soviet-made air conditioning system can be seen – with original labeling – and signs in Russian are on display on the walls.

The platform is also a vantage point to see the extensive array of heat-exchangers put along a sidewall of the central hall – atmosphere control was of primary importance for the relatively delicate nuclear warheads. Each of them traveled and was kept in a pressurized canister. However, also the storage site was under careful atmospheric control.

To the opposite end of the bunker, the inner tight door of the second entrance can be clearly seen, ahead of another suspended platform. The warheads left the bunker for maintenance (they might have left also for use, but this never happened, except possibly on drills) from that entrance, which had a loading platform outside for putting the warheads on trucks (this can be better seen in other Monolith sites, like Urkut in Hungary, or Stolzenhain in Germany).

Down on the lower level, the main bunker hall gives access to one side to four big cellars, where the warheads spent their time in storage, and to the other sides to technical rooms. The pavement in the storage cellars features the original metal strongpoints, used to anchor the trolleys for the warheads to the ground. This was in case of a shockwave investing the site in an attack, to avoid the trolleys moving and crashing against one another. The original hooks with spherical joints to link the trolley to the strongpoints are also on display.

The storage cellars today have been used to display informative panels, with many interesting pictures and schemes. These include some from major sites connected with the history of nuclear weaponry in the Soviet Union (like from the test site of Semipalatinsk) and the US (like the Titan Museum near Tucson, AZ, covered in this post).

A few former technical rooms are used to store much original technical gear. This ranges from spare parts, tools and personal gear like working suits left by the Soviets (most with signs in Russian), to items ‘Made in Czechoslovakia’ or even radiation detectors from Britain and the West, gathered here for display and comparison.

Some of these spare parts are wrapped and sealed in Russian, looking like they were cataloged back in the time of operations.

In the main hall, many rare vintage pictures retrace the presence of Soviet military forces on this site as well as others in Czechoslovakia. Magnified copies of rare pictures portray the trucks, canisters and the very warheads likely involved in transport and storage in Javor 51. Actually, much mystery exists around the deployment of nuclear ordnance by the USSR outside its borders (not only to Czechoslovakia). Historical and technical information today made available, even to a dedicated public, is very limited, making this chapter of Cold War history even more intriguing.

Again in the central hall, cabinets for monitoring the nuclear warheads can be seen hanging from the walls, painted in blue. Each warhead used to be stored in a canister, which was periodically linked to these cabinets to check the inner atmosphere, temperature, etc., in order to monitor the health of its very sensitive content.

A large part of the technical/living rooms has been preserved in its original appearance. You can see parts of an air conditioning system, a big water tank, a toilet, a now empty bedroom for the troops. The bunker was constantly manned inside by typically six people, who operated in shifts. They did not sleep there, nor used the toilet much due to poor drainage. However, these facilities were used in drills, and were intended for the case of real war operations, when the bunker might have been sealed from the outside.

The electric cabinets take a dedicated room, like the huge air filters and pumps (Soviet made), installed to grant survival of the people inside the bunker in case of an attack with nuclear weapons or other special warfare. Clearly, the level of safety in the design of the bunker stemmed from the fact that it was considered by the Soviet as a a strategic target for NATO forces.

The last technical rooms host a big Diesel generator, supplied with air from the outside, and a big fuel tank in an adjoining room. Many labels bear writings in Russian, but the generator appears to be made in Czechoslovakia. The bunker was linked to the usual electric power grid of the region, and the generator was intended for emergency operations, in case the grid was lost or the bunker was isolated.

From the technical area, it was possible to access or exit the bunker, via a human-size airlock. The innermost tight door can be seen painted in yellow, with a locking mechanism resembling that of the major tight doors for the missile warheads. Outside the airlock, climbing three levels of ladders was required to get to the surface. This was the normal access to the bunker for the military technical staff, except when warheads arrived or left the storage (this was made via the major entrances, as explained).

Back outside, the second bunker, Nr.2, can be found at a short distance from the former. Nr.2 is being prepared for an exhibition on technology. At the time of writing, it can be toured except for the technical/living rooms. It is in a very good condition, and allows to get similar details as the previous Nr.1 on the construction of this type of facility – including the heating/air conditioning system.

The blue cabinets for plugging the canister for routine status checking and maintenance can be found also in Nr.2 in good shape.

Clearly visible here are the doors closing the technical areas and the warhead cellars. The latter were monitored for security just like the external airtight doors of the bunker, each with a sensor telling controllers whether the cellar was locked or not.

The airlock is covered in soot, possibly the result of a fire. Ahead of the entrance, the unloading platform is very interesting, having a unique set of light doors which had to be opened to allow trucks to come in. The concrete part of the platform appears slightly off-standard, with a short lateral concrete ramp, giving access to the main platform from one side. Parts of missiles – original – are being gathered in this area for display.

Monolith sites include two bunkers, which are the core of a strongly defended fenced area. In Javor 51, fences except the external one have been removed for the safety of visitors (rusty barbed wire can be very dangerous). These can still be found in other similar installations (see here). Similarly, the troops and technicians working on site lived in purpose-built housing, segregated from local communities. In Javor 51, this housing still exists, but cannot be visited.

Leaving the place, you can visit the nice visitor/gathering center, and even find some interesting souvenirs!

Getting there and visiting

All in all, the Atom Museum prepared at Javor 51 is a top destination for everybody interested in the history of the Cold War, nuclear warfare, Soviet history, military history, etc.

Credit goes to the owner of the place, Dr. Vaclav Vitovec, who is leading this remarkable preservation effort, and is a very knowledgeable and enthusiastic guide to the site for those visiting. Dr. Vitovec is also the owner of the border museum in Rozvadov, covered in this post.

The Javor 51 site is actually fairly well known at least to a dedicated public, having been visited by historians, scientists and notable figures – including Francis Gary Powers, Jr., who is very active in preserving the history of the Cold War.

The commitment of the museum’s managers is witnessed also by the nice website (also in English), where you can sign-up for a visit on pre-arranged days – as of 2022, all Saturdays in the warm season – or contact the staff for setting up a personalized visit. It is nice to see a good involvement by the local population (the great majority of visitors on regular visits are Czech), including many from younger generations. The exhibits tell much on the peaceful use of nuclear energy, and this is a major topic in the guided tour in Czech. Actually, the Czech Republic has a strong nuclear tradition, with many power plants in use, and a commitment for the development of nuclear energy in the future.

The location is around 25 miles southeast of Plzen, or 60 miles southwest of Prague. Easy to reach by car. The exact address is Míšov 51, 33563 Míšov, Czechia. Full info on their website. Visiting on a normal scheduled visit is on a partly-guided basis, meaning that you will get an intro (in Czech) of around 40 minutes, than you will be allowed to access the bunkers and visit on your own, for all the time you like. You might end up spending more than 2 hours checking out the site and everything is in it, if you have a special interest for the topic. Dr. Vitovec is fluent in English, and can provide much information upon request.

Javor 52 – Bělá pod Bezdězem

The Monolith-type site Javor 52 has been willingly demolished, likely by the Government of the Czech Republic, as it was the case for most other similar (or more in general, Soviet-related) sites in Poland and Germany.

However, it was hard to get completely rid of any trace of an installation so bulky and reinforced. Therefore, some remains can still be found and explored.

Some technical buildings still in use close to the bunkers may have been there from the days of operation.

Getting close to the bunker area, traces of the multiple fences originally around the site can be found, either in the trees or in the vicinity of unmaintained roads. Wooden or concrete posts with fragments of barbed wire are clearly visible. Also reinforced concrete shooting points can be spotted in the wild vegetation.

As typical, two bunkers were erected on site, and similarly to Javor 51 (see above), in Javor 52 they are aligned, with the entrances all along the same ideal orientation.

The bunkers in Javor 52 have been interred, so that they are now hardly noticeable from the outside, except to a careful eye. Looking inside the eastern one, it is possible to get a view of the open doors of the main airlock, providing a distant view of the inner main hall.

Descending through the lateral human-sized airlock is not possible except for a short length, from a concrete manhole on top of the bunker.

The western bunker is in a better general condition, and the main hall still retains a pretty unique writing in Russian. The ladder descending from the suspended platform has been substituted with a posthumous, regular ladder. Much metalwork has disappeared though, including the heat exchangers, the crane, and the tight doors.

Between the bunkers, a concrete pool can be found – still watertight! – with a function which is hard to guess. A pool for civil use was installed in Stolzenhain (and reportedly also in Javor 52, but I had not the time to watch out for it), but this was in the low-security of the site, far from the bunkers.

Getting there and moving around

Access to this place is possible without violating any property sign, but is clearly not encouraged. Going unnoticed is made tricky by the presence of a public facility nearby – a shelter for foreigners and some education activity. Parking out of sight is possible along the road 27235, north of the complex and to the west of the road – trailheads and corresponding parking areas can be found there. Check out some satellite map to find a way to the exact location of the bunkers – their respective entrances are approximately here (eastern bunker) and here (western bunker).

I visited the site in 2020, and the entrances appeared very dangerous and easy to seal in a permanent way. I do not have any further update, but would suggest to go prepared to find definitively interred and totally inaccessible bunkers.

Javor 50 – Bílina – Quick note

As of 2020, the site of Javor 50 is in a peculiar state of ‘conservation’. The place is closed to the public, but entering would be basically unimpeded, since the external fence to the former military base is mostly collapsed and interrupted. The Soviet quarters insider still have much to offer – including writing in Russian, a scheme of the base, and much more. Likely, the bunkers are also still in a relatively good shape.

Much surprisingly though, somebody is living there with watchdogs, in miserable conditions, keeping visitors out. It is likely that an official visit may be booked by getting in touch with the municipality, since it appears that the site is not used for anything. However I was not successful in connecting with anybody there, therefore I have no suggestion on this point. The of the main entrance is here.

Soviet ‘Monolith’ Nuclear Bunkers in Poland – Survivors & Ghosts

Since the beginning caught in the storm of WWII, Poland saw its border changed again in 1945 by the Western Allies and the USSR – the lack of natural borders meant that fate for this Country several times over the centuries. Furthermore, as a massive flow of Soviet forces had been pivotal in repelling Hitler’s forces, similar to other nations sharing a border with the USSR, Poland found itself deep in the sphere of influence of Stalin’s Soviet Union. A communist dictatorship was installed starting 1945, due to last until the end of communism in Europe in 1989.

As a matter of fact, Poland turned out to be by far the most populated and largest of Eastern Bloc countries. Strategically placed in the middle between the USSR and free Western Europe, with a wide section of the Baltic shoreline and a huge, mostly flat territory, similar to the German Democratic Republic nearby, Poland was the theater of a significant militarization effort by the Soviets. Not only the Polish army received Soviet war material in large stocks over the full span of the Cold War, but the Red Army also actually had significant assets scattered over Polish territory – its huge Northern Group of Forces being stationed there, with tanks, aircraft, dedicated bases, firing ranges, as well as several tens of thousand troops and their families, making for a kind of military colony of the USSR.

What is possibly less known is that also Soviet nuclear weapons were stationed in some satellites of the USSR, like the GDR (see this and this chapters, for instance), Hungary (see this chapter), and of course Poland.

Some elements of the global picture have been introduced in another chapter, dealing among other things with a Basalt-type bunker built for storing air-launched nuclear systems, on the premises of the Soviet airbase of Wiechlice (Szprotawa). Yet as can be argued from the general map of of nuclear depots known to Western intelligence, dating from 1979 (‘Warsaw Pact Forces Opposite NATO’, Vol.I-II, CREST record number 0005517771, declassified and released in 2010, here), there were also three major depots of the Monolith-type in Poland. Similar to Stolzenhain and Lychen in the former GDR (see this post), these depots were larger, multi-chamber storage facilities, intended to store primarily missile warheads for longer periods, for instance to complement the SCUD launch system for theater missiles.

The uniqueness of Poland in the panorama of Cold War archaeology lies in a generally positive attitude towards preserving some traces of this dramatic piece of recent history, when the map of Europe was markedly different from now, and the western world found itself multiple times on the verge of a nuclear confrontation, to be fought on the very territory of now wealthy Core Europe. As a result, an impressive number of war museums putting on display military stuff from all the 20th century can be found scattered over the broad territory of today’s Poland.

Even more important, a certain number of former Soviet military installations are being either actively preserved, or at least not condemned through demolition works or re-assignment to improbable new uses. This is despite a totally justified negative attitude towards the Soviet occupation forces and communist dictatorship. This attitude marks an unusual difference between the cultural attitude of the fierce Polish people towards recent military history and Soviet occupation, with respect for instance to Germany or Hungary, where the comprehensible dislike for the Soviets has taken a shape in leaving behind – i.e. more or less demolishing – every trace of a Soviet military presence, and especially in the former, reducing military museums to a minimum.

Among the most prominent Cold War relics you can find in Poland are the three Monolith-type nuclear warhead bunkers mentioned above. One of them – the Podborsko site – has been restored with 90% original material, and makes for a world-class, top-tier museum in the panorama of Cold War military history. The other two, Brzeznica-Kolonia and Templewo, have been left to nature and have now become ‘Soviet ghosts’, but they are advertised with panels, providing some info, and while access is not encouraged, a quick look inside the bunkers, as well as freely walking in the former premises of these bases, is of course possible.

This post covers these three Monolith-type sites, with a focus on the unique preserved Podborsko site, which needs to be on the shortlist of everyone with an interest in Cold War technology, as well as in the history of the nuclear stockpile. All sites were visited, and all photographs taken, on a trip to western Poland in summer 2020.

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Sights

All three sites are in northwestern Poland. GPS coordinates are provided in the respective sections. Despite being not too much afar from each other, due the relatively slow connection roads in the area, visiting all three places in one day is not possible. Furthermore, the area is quite dense in both general interest and Cold War related destinations, so I would advise planning a trip to this region of Poland and listing these sites among other destinations.

Podborsko Site – Objekt 3001

A good specimen of a Monolith site, Podborsko – or Objekt 3001, as per the official military listing of the Cold War years – was centered on two large half-interred bunker, each with two big side-wards opening tight doors at ground level, providing access to the interior with the trolleys used to move the nuclear warheads from the transport trucks to the cellars.

For an increased protection in case of an attack to the site – likely listed among targets of strategic value by Western Countries – a second tight door was put immediately next to the external one, creating a tight, blast resisting and insulated airlock between the interior of the bunker and the outside world.

Both doors to the two ends of the airlock can be – and are – opened via a manual crank system. Two men are needed to actually move the doors however – they are really heavy! A servo-assisted system was in place originally.

An interesting detail is the original sensor for the door status, part of a security system of the base.

Similar to their US counterparts, the Soviets took the problem of security of the nuclear arsenal pretty seriously. Each door on the path followed by the warhead from the outside to the cellar, including the airlock doors as well as the cellar doors inside the bunker, were associated to a trigger. When the corresponding door was opened, the trigger sent a signal via a dedicated cable link to the headquarters of a dedicated branch of the Red Army offices in Moscow, Russia, which was kept constantly updated on the status of each critical door in the depot. The link was via purpose-designed vacuum-protected cables – the actual wiring ran along a vacuum manifold, so that in case of the cable was bitten and the vacuum manifold collapsed, an emergency signal was immediately sent to the nearest nodes of the network, allowing surveillance staff to intervene promptly.

The opening of and closing procedure of the airlock doors involved communication with a post in Moscow too, which started with the local guards communicating their intention to open the doors via a system housed in a blue cabinet besides the tight door. As the signal traveled from the bunker to the headquarters and back, the opening of an airlock was not a quick operation! Original writings in pencil can still be found in the cabinet.

Past the airlock, you land on an elevated concrete platform. From here the warheads were moved to the underground floor via a mechanical crane. This is still standing today, with limit indications in Russian.

From the platform you get an excellent lookout of the bunker structure. You can see a twin suspended platform to the opposite end of the underground floor, with a tight door shut closed. Along the long sides of the main hall, on the underground level you see several doors. On the right hand side, big sliding doors painted in white give access to the cellars, where the warheads spent most of their time in rest. On the opposite side are smaller man-sized doors, giving access to the technical area, with provision for the men of the permanent bunker watch.

The stairs leading downstairs are among the few complements to the original structure – they have been put in place to ease visiting. Originally, the underground floor could be reached from the suspended platform only via a lateral manhole with a vertical metal latter.

The warheads are long gone today – the site was built in the late 1960s, and was emptied of its strategically relevant content in the late 1980s, to be finally ceded back to the Polish government after the withdrawal of all Russian forces from Europe. The cellars today are mainly empty, and used to showcase interesting items related to the site.

First, you can see a scale model of the entire site. In Soviet times, the place was a full scale military base. It included a separated area with living facilities for the troops and their families, who ran the base with both technical and surveillance tasks. Today, this area has been taken over by the government, and used as a prison – Podborsko is rather secluded and far from populated areas on the Baltic coast. Furthermore, as said there used to be two twin bunkers. Today only one has been restored, whereas the other is sealed and waiting for reuse. Between the sectors of the base multiple fences with barbed wire, concrete walls, foxholes and other deterring/defense devices and systems were in place, making the innermost part of the base with the bunkers rather inaccessible.

An original armored cabinet from the time of operation is still in the corner of a cellar, its original use is uncertain.

In another cellar you can find everyday items and relics from Soviet presence in the area. These range from toothpaste to children’s toys. Also more military-related items, like cartridge boxes and even original Soviet military dog tags have been found scattered over the area!

You can also find weapons, a scheme of the base in Russian, anti-radiation suits, and parts of the body, control and guidance systems of a Soviet SCUD theater missile – the corresponding warheads being the main business in Podborsko. There is also a copy of the plan of an attack scenario for Western Europe, showing some targets on the respective sides of the Iron Curtain.

One of the cellars has been left empty, with a mock-up of a warhead, resting on one of the original trolleys. This is particularly evoking, despite being just one out of the high number of warheads usually stored in a cellar. The actual number of warheads residing in each Soviet storage over the years is still today not totally clear. However, reportedly former Soviet staff support there was in a single Monolith bunker in Poland enough nuclear material for the whole attack plan over Europe, meaning a number of several tens warheads per site.

The trolley is original as said, and it shows the function of the slots on the ground of each cellar, which allowed anchoring the trolley firmly in position. This was possibly needed also in the extreme case of a blast hitting the bunker, so as to avoid any unwanted displacement of the trolleys.

A fourth cellar displays a set of panels, outlining the history of the Cold War.

As said, the security triggers telling the status of the door can be found close also to each of the sliding doors of the cellars.

Before moving to the technical area on the other side of the bunker, a look to the central hall reveals a number of original material. In particular, you can find an interesting set of instruments, handles and gauges packed together in a metal cabinet. Their function was that of monitoring the state of each warhead. Nuclear material needs to be stored in precise conservation conditions, so warheads were kept in dedicated cases. These were inspected regularly by connecting them to the monitoring system and recording the corresponding gauge readings. Traces of the positioning markers for an inspected trolley can be found close to the cabinet, painted on the ground.

Another conspicuous sight in the main hall is the heating system, needed to keep the inside atmosphere at a constant assigned temperature and humidity level, to guarantee the health of nuclear material. A big array of heat exchangers takes the top part of a side wall in the main hall.

The technical part is made of two main parts, and is accessible on the long side of the hall opposite to the cellars. One part is made of a blind sequence of three narrow compartments. Here you can find a case for manipulating dangerous chemicals, with protection gloves once protruding inside. Nearby, a sink and some cabinets recall a medical room.

This area was designed to manipulate and check the triggers of nuclear weapons in use at the time of construction of the Monolith bunkers (late 1960s). These made use of reactive materials, thus requiring some precautions and a complex maintenance procedure. They were phased out soon after the construction of the site though, so this part of the bunker was basically unused since that time. A tight door connects this area to the main hall.

The second part of the technical area is arranged along a U-shaped corridor, starting and ending in the main hall. Similar to the previous technical part, a small sealed door connects the corridor to the main hall.

The first technical rooms you meet are related to climate control.