Building 210 was the Avionics Building for the TR-1 spy planes (the successor of the U-2 spy plane) on USAF Alconbury Airfield, it was also known as Magic Mountain or Dragon Mountain depending who you talk to.

In the late 1980s this hardened bunker was built for processing the photos and information collected by the TR-1 Spy planes, the TR-1 was nicknamed “Dragon Lady” which is where the bunkers “Dragon Mountain” name came from.

Most of the bunker is on the ground floor with plant and generators on the basement level it has a large concrete blast cap on top designed to take the impact of an attack.

The building is apparently one of the last bunkers that the US built and is now listed, it opens once a year for tours. These pictures are from 2023, I first visited in 2006 and since then little has changed except now the bunker is much cleaner and better maintained.

The following pictures show the Exterior, Covered entrance tunnel, the decontamination suites for personnel and equipment as well as the rooms where the data would have been processed however no equipment remains except the switchgear giving us a glimpse of the amount of hardware that needed power.

The Cambridgeshire County Council Cold War Emergency Headquarters Bunker was situated under the council offices in Cambridge city centre, it is a single story structure at the basement level built alongside the carpark in 1987. It has a soil mound on top and was a replacement to the original emergency centre which was in the basement of nearby Shire Hall.

After it was decommissioned as a “Nuclear Bunker” it became a generic Emergency Centre used for various large incident in the 90s and now it is used as a store for the Natural & Historic Environment department.

Council staff would have entered the bunker using the internal stairways from the offices down through the carpark and from there through the blast doors.

Once in the lobby they would be signed in at the reception desk before proceeding to their designated rooms, The generator and plant rooms are on the left as you enter, the generator itself is noticeably small and I’m told it wasn’t actually powerful enough to run the entire bunker.

There is one corridor that runs the length of the bunker and all the other rooms come off this, as usual the operations room is the largest and at the far end are the toilets and showers.

Beyond the toilets is an Exit lobby, this would also have served as an entrance for people entering after the bunker was “activated”, there would have been a small decontamination shower located here.

I have made a 360 Degree virtual tour of the bunker https://iamanerd.org.uk/360/cambridgeshire-county-council-emergency-hq/ and below are a few photos from my visit.

Thankyou to the Cambridgeshire County Council Natural & Historic Environment department for facilitating my visit.

Norfolk County Hall was built in Norwich in 1966, the lower basement Rooms B38 to B47 housed the County Emergency Headquarters. The Emergency Headquarters consisted of several rooms along one corridor with a blast door at each end.

There was zero information or references online about this Emergency headquarters but based on a hunch I contacted the County Council to enquire about their Cold war Emergency headquarters and its status.

I learned about this protected basement area however I was informed that in 2019 the lower basement was stripped and refurbished with little trace of the HQ remaining, I have since pieced together as much information as possible from the archives and I was also lucky enough to visit what remains.

From at least the 1980’s the basement would have been laid out as above, the various operations rooms were along the left hand side of the corridor with the Communications and briefing rooms on the right with a store and Kitchen. Administration support would have been before the blast door outside of the protected area.

Protective shutters could be fitted over the external windows in the basement rooms that didn’t form part of the protected areas. These rooms could be used as overflow to the main “bunker” or as specified in the civil defense plans.

Much of the equipment in the HQ remained until it was refurbished however its all gone now, including a small BBC radio broadcast desk and RAYNET (Radio Amateurs Emergency Network) station there were also a pair of key switches for controlling the fire alarm sirens. Incidentally, according to a 1994 addendum to the manual, in the event of a “Bomb Alert” the fire alarm bells would sound 2 second blasts for approximately 5 minutes. When deemed safe 2 minutes of short blasts would indicate the “All Clear” condition.

Below are some Archive photos of the External blast protection brackets, broadcast equipment and alarm controls in the rooms from 2015 (No longer present):

I visited in 2025 and although it is now just a corridor you can still see glimpses of its former life.

As you enter what was the Emergency Headquarters you are greeted with the remains of a door frame where the first blast door would have been hung, beyond which is a standard white washed blockwork corridor with several rooms off it. These have all been stripped and renovated (including the kitchen) for use as storage rooms they appear to be the original doors with vents still in place.

At the far end of the corridor to the right is a plant room with air handling unit, filters and a backup generator (All unused).

Finally there is one remaining blast door which leads to the emergency exit, photoluminescent tape is still visible on the vinyl flooring which would have marked the escape route.

The basement rooms are used for storage by the County Council and are not accessible, these photos are from an organised visit in March 2025.

During WW2 this was a Black propaganda site and home to the Aspidistra Radio transmitter. the bunker there was built during WW2 for this purpose.

In the early 1980s the Aspidistra bunker was stripped out and converted into a 3 level deep RGHQ which was subsequently sold to Sussex Police in 1992. They still own the site today and use the site for training.

Below are some photos from an organised visit to the RGHQ in may 2024, the bunker isn’t used these days. It’s interesting as you can see sections where the WW2 and Cold war extensions meet.

The rest of the site still contains many of the WW2 buildings in various states of repair, Its primary use now as a Police training facility has taken its toll on the buildings and they show the battle scars from many years of Police exercises.

One especially interesting building is the orignal Aspidistra radio broadcasting hall, it was designed by an architect known for his cinema design which can clearly be seen in it.

Alconbury Airfield was originally built in WW2 as an RAF bomber base, the USAF took over in 1942 and In 1995 the Airfield was handed back they do continue to operate from the rest of the site. I’m not going to bother regurgitating the history of Alconbury as it is well documented online already.

In the mid 2000s I worked on the airfield for a company based in Hangar 15 and was I very lucky to visit most of the empty airfield buildings.

Unfortunately I lost most of my photos when a HDD failed on me in 2008 (incidentally this is the reason I love my NAS drive) so many have been lost forever. The few that remain I have posted below, however some are incredibly low resolution.

I will do a separate post for Magic Mountain, Dragon Mountain, Building 210, Hardened Avionics Building/bunker (or whatever you wish to call it) which I originally visited in 2006, the only photos I have are from a visit in 2023.

Some General photo’s of the tech site, airfield and buildings 2005-2007:

Hardened aircraft shelter (HAS) 3001, The standard HAS on Alconbury are identical to those on all US airfields of the era, There are also some wider HAS built specifically for the TR-1 Spy planes below are a few photos from a standard HAS, building 3001:

On October the 16th 2007 Hanger 4001 which was occupied by Excel logistics at the time Burned to the ground.

Rex Keegan emailed me this at the time “4001 was the first TR-1 Shelter, (called Weather Shelters), constructed and delivered. Prior to these 5 shelters, all TR-1 work was accomplished in Hangar 15 or in part on Hangar 94. These shelters were built to launch aircraft from and had a small back door for the tow vehicle to drive through when towing the aircraft inside, (the TR was towed backwards) and also for the exhaust to pass through when the engine was running. The same concept was used in the hardened shelters for launch. The front door was a bi-forcated overhead contraption with three huge hydraulic pistons. (a maintenance nightmare) The 4 shelters shown were built on the West side of the Old North Runway, near runway side. The 5th shelter was built on the East side of the Old North runway overtop of the old burn pit/dump. 4005 was used as a fuel repair and corrosion control facility, and had an AFFF fire defense system.
The four shelters were never used for real world missions. Only training missions were ever flown from them, because Hangar 15 had all the equipment and power necessary for preparing a TR-1 for a particular mission. These continued to be generated and launched from that area until the hardened shelters were able to be utilized.
In spite of a lack of facilities and a shortage of equipment, the TR-1 missions flown during their time at Alconbury were deemed highly effective and so technically well advanced over that of our adversaries that their success greatly contributed to ending the cold war.”

Below are some pictures from Hangar 15 when occupied by ELP an Events, TV and Broadcast Lighting company:

Finally for now, here are a few pictures from 2023 of a few of the remaining airfield buildings:

RAF Barnham was home of the 94th Maintenance Unit, this was where the payload of the UKs first Nuclear Deterrent the “Blue Danube” was maintained. The payload had a very short half-life so every few weeks returned here via truck from the southern V-Bomber sites for maintenance.

There was a sister site at RAF Faldingworth that maintained the northern airfields but this is the only complete example remaining more information can be found here https://rafbarnham-nss.weebly.com/

In 2022 with permission from the site owners we took a couple of hundred 360 photos, I’ve used a small selection to create a virtual tour of this amazing location, please enjoy.

Click below for the virtual tour:
https://tour.panoee.com/barnham360