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Jonastal, Ohrdruf

One of the many Third Reich construction projects that was started but never finished was a series of underground complexes in central  Thueringen, southeast of the city of Gotha (near the concentration camp at Ohrdruf, the first such camp found by the Americans on German soil). This project had several code names, depending on what part was meant, and the names also changed over time - the following names were used for all or part of this complex - Siegfried, Olga, Burg, Jasmin; the designation S/III was sometimes used for the entire project. The main works were dug into a hill forming the north side of the Jonas Valley, between Crawinkel and Arnstadt. This part of the project was reportedly intended as a last-ditch headquarters facility for Hitler and his staff, should they fall back from Berlin into the interior of Germany (some reports say Hitler actually spent the end of March 1945 in this or another nearby underground Führer Headquarters). Other theories say this or a nearby site were intended for production of the intercontinental "Amerika" rocket, and even testing and production of a Nazi atomic bomb. Most of the complex never advanced much further than the tunnel digging stage, and the Soviets blasted most of the tunnel entrances after the war. The exact purpose of this facility remains in doubt, as does its code-names ("Siegfried" and "Olga" may actually have been names of other sites).

Military Training Ground
There had been a military training ground at Ohrdruf since Imperial times. It was a large, rugged area of upland, nowadays disused and strewn with shells and other military scrap. Through binoculars small parts of the ruins of Amt 10, described below, can be made out but not visited.
During 1936/38 an Army underground telephone/telex exchange known as Amt 10 was built in the limestone strata below the TUP. Its entrances were disguised as chalets. The bunker was 50 feet down and measured 70 x 20 metres. Both floors had a central corridor about 3 metres wide with rooms either side, and 2 WCs. End-doors were gas-proofed, the installation had central heating, air was supplied under pressure, water drawn from a spring 600 feet below. A 475 hp ship's diesel was on hand as the emergency electrical generator, and this piece of equipment plays an important role in understanding the Ohrdruf mystery.
Col Robert S Allen, a Staff officer with General Patton's Third Army described in his book "Lucky Forward - The History of Patton's Third Army" (New York, 1947) a completed underground reinforced-concrete metropolis 50 feet down "to house the High Command". It was on two or three levels and consisted of galleries several miles in length and "extending like the spokes of a wheel." The location of Hitler's FHQ was not stated and Amt 10 was described misleadingly as "a two-floor deep concrete shelter."
If the structure was built like a wheel,, the FHQ would logically be at the hub, and Amt 10 was at the hub. Allen's description of Amt 10 as having two floors on April 1945 conflicts with the evidence of two persons who worked there: one hinted that there were more than two floors, the other testified there were three. The latter witness also stated that Amt 10 was two great bunkers of the same size, each of three floors, but not connected except by underground piping. Each bunker was guarded on each level by an SS sentry and passes for each entrance were not common to both. The most likely explanation is that the second bunker was constructed in 1944 at the same time as a third level was added to the first Amt 10 bunker as the Fuehrer-suite.
As regards the second bunker, a witness stated that in 1944 there was an installation below the TUP which created an electro-magnetic field capable of stopping the engines of a conventional aircraft at seven miles. During the war, the Allies never photographed Ohrdruf from the air, nor bombed it, even though their spies must have assured them it was crawling with SS and scientific groups. A German electro-magnetic field whichinterfered with their aircraft at altitudes of up to seven miles is admitted by a 1945 USAF Intelligence document. The USAF suspected that it was a device to bring down their bombers, but it obviously had some other purpose, or it would have been operating below Berlin.
Many Arnstadt witnesses described occasions when electrical equipment and automobile engines cut out. They always knew when this was about to happen, for the ship's diesel engine at Amt 10 would smoke. A diesel motor is not affected by an electro-magnetic field. In 1980, Russians scientists were still able to measure the field on their equipment, but they were never able to identify the source.
The OKW and Luftwaffe War Diaries and all copies of them for the period March 1945 have disappearedand are suspected to be in American keeping.
On 7 April 1945 the US Atomic Energy Commission inspected various underground workings at Ohrdruf and removed technical equipment before dynamiting surface entrances. The US authorities have classified all 1945 documents relating to Ohrdruf for a minimum period of 100 years. 

Fortunately for researchers, in 1962 a quasi-judicial tribunal sat at Arnstadt in the then DDR to take depositions from local residents for an enquiry entitled "Befragung von Buergern zu Ereignissen zur oertlichen Geschichte". The enquiry was principally interested in what went on at the Ohrdruf Truppenuebungsplatz (TUP) in the latter years of the war. The depositions became common property in 1989 upon the reunification of Germany and may be viewed at Arnstadt Town Hall.