The site is part of the German WWII Project Riese (Giant) in the Owl Mountains (Góry Sowie )of southern Poland. It operates as a museum site known as the Osówka Podziemne Miasto (Underground City).
The underground complex has two entrances; there is another short unconnected excavation but we weren’t able to locate this entrance. Our guided tour took us into the mountainside and we could quickly see that more of the complex had been concrete-lined than nearby Rzeczka or Włodarz. The guardrooms appeared almost complete; we were told that it is one of the few locations where hibernating bats have been found.
Next, a surprise, as the tunnel rises up steps perhaps 15 metres. Whatever the purpose of the complex this seems very odd; whether used for manufacturing, storage or personnel protection this would certainly have hampererd operations. One of the plans marked this as a fault but we didn’t have time to look properly at the geology before we had to move on. Beyond this level change we entered another grid layout, with some of the tunnels widened to form huge halls. One of these still had the extensive arched shuttering over which concrete had been poured; a dramatic snapshot of ‘work in progress’.
Like Włodarz, part of the complex is flooded but we did not have the time to explore this by boat. We did, however see a shaft reaching perhaps 50 metres to the surface with a diameter of around six metres. The tunnels have been used for the filming of a number of science fiction films and the remains of the set sit gently decaying alongside the more usual rusting wartime artefacts.
On exiting the underground section the more energetic of the group ascended a long steep hill to explore the top of the complex at our own speed. This was one of the highlights of the visit. First we were able to see the top of the shaft recently viewed undergound. Around this were a number of areas that looked like the bases of wartime huts – perhaps for construction workers. These in turn led to a section of underground tunnel which appeared to have been designed as a conduit for cables or piping but was high enough for pedestrians.
This tunnel was unfinished and alongside it we once again saw huge stockpiles of bags of cement, showing that the works must have been abandoned at great speed. Of course cement needs aggregates and sand and we were surprised to see large silos – large enough for many tons – alongside the stacks of cement. It seems likely that the shaft was being used to feed in supplies of concrete.
Opposite a trackway from these silos was a vast building known locally either as the Casino or Officers’ Mess. It is around 50 metres by 13 metres with walls around 0.5 metres thick,and is almost complete with access through large window openings easily achieved. The speculation is that it served as some sort of headquarters building. Inside the building was bare but interestingly it still retained extensive wood-wool boards to the ceiling; this was an early example of their use as permanent shuttering - I can’t recall seeing this aspect at other German-built World War II sites.
Around 250 metres away was the second large above-ground structure. Conventially known as the Power Station, this is built only to ground level and measures around 30 metres square. The structure contains a number of manholes, hoppers and conduits which were explored by the party using original ladder staples. Extensive reinforcing bars showed that an above-ground structure was planned but the exact purpose of the building is unknown but some sort of power-generation seems as likely as anything.