Książ Castle Underground

Half a kilometre of concrete corridors and halls cut 50 metres beneath Poland's third-largest castle – and nobody knows to this day how big the whole complex really is. The Książ Castle Underground is an unfinished Nazi German project from 1944–1945, dug by prisoners. Visitors have only been able to go down since 16 October 2018, when the Underground Tourist Route opened.

History: a headquarters that was never finished

In 1943 the Third Reich took over the castle from the Hochberg family, and from 1944 the Todt Organisation began converting it into one of Adolf Hitler's headquarters. This was linked to Project Riese ("Giant"), a network of underground complexes in the Owl Mountains and around Wałbrzych. The work was done by prisoners: in May 1944 a sub-camp of the Gross-Rosen concentration camp was set up here. A 40-metre lift shaft was sunk in front of the main portal, with tunnels and a shelter below the castle. The conversion also destroyed most of the historic interiors.

Historians still disagree about what the tunnels were for. Some see a command headquarters, others a factory or a store for documents and valuables. Construction was never completed, and after the war Soviet troops stationed here vandalised the castle. Since 1971 part of the underground has housed the Lower Silesian Geophysical Observatory of the Polish Academy of Sciences.

How big is it really?

The known underground areas cover about 3,200 m² – a figure based on the amount of concrete delivered to the site. According to notes by Albert Speer, the Reich's armaments minister, the complex may be up to twice as large. The corridors were reinforced with Portland cement, while sections cut into bare rock still await investigation. Along the route you see smooth concrete, raw rock and places where the digging simply stops – a clear sign of how hurriedly the work went on in the last months of the war.

What you will see

• Concrete corridors and halls about 50 metres below the Courtyard of Honour.
• Bare rock workings, where digging stopped in 1945.
• The story of the prisoners who dug the tunnels – the guides return to it throughout the tour.

Tripto tip

The route is about 0.5 km long, and you descend mostly by stairs – roughly 50 metres vertically. The temperature is 6–12°C all year, so bring a jacket even in July and wear flat, comfortable shoes. Visits are guided, at set times; be at the meeting point 15 minutes early, as the walk from the gate building alone takes about a quarter of an hour. Group sizes are limited, so it is best to buy tickets online on the castle website, which lists current times and prices. Children under 4 and pets are not allowed; the route is not accessible to wheelchair users and is not recommended for people with claustrophobia, circulatory problems or in late pregnancy. It combines easily with a visit to the castle itself, its terraces and the Palm House in Lubiechów.