The Riese Complex was a Nazi Germany construction project from 1943 to 1945 consisting of seven top-secret underground structures located in the Owl Mountains and Książ Castle in Lower Silesia.

The actual purpose of the project remains unclear and Riese remains one of World War II’s greatest mysteries mainly due to a lack of documentation. Some historians suggest that the structures were planned as a network of underground factories and the tunnels below Książ Castle were to house an HQ element, perhaps an addition to Hitler’s collection of reinforced command centres.

Two things are certain, the size of the project was immense and none of the constructions were finished. Only a few tunnels were reinforced with concrete. Project Riese was abandoned at the initial stage of construction and only 9 km (25,000 m2, 100,000 m3) of tunnels were dug out.

A massive network of roads, narrow gauge railways and bridges were constructed to connect excavation sites with the nearby railway stations. In total, some 90,000 cubic metres of tunnels were carved into the mountains, the work involved to do this was strenuous and involved cutting down thousands of trees, building dams, digging reservoirs and drainage ditches, blasting rocks with explosives and reinforcing caverns with concrete and steel.

Seven major access points were constructed to separate tunnel systems at Walim-Rzeczka, Włodarz, Jugowice, Soboń, Sokolec, Osówka and Książ Castle.

To build these giant structures, the Nazis used prisoners of war, prisoners from concentration camps and forced labourers. Many of these workers lost their lives due to disease, malnutrition, exhaustion & dangerous underground works.

Initially, concentration camp prisoners were not used; however a typhus epidemic occurred amongst the workforce in December 1943 significantly slowing down production. Hitler handed over supervision of construction to Organisation Todt, headed by Albert Speer, Hitler’s chief architect and engineer and around 13,000 prisoners of the camps were put to work, many conscripted from Auschwitz concentration camp.

Interestingly, Albert Speer himself stated that the Riese Project involved some 213,000 cubic metres of tunnels. Today, less than 100,000 are accounted for, suggesting that there are many tunnels and parts of the project still to be discovered. This is technically supported by the existence of narrow-gauge railways and plumbing that appear to lead nowhere, witness accounts also support this account.

113,000 cubic metres of undiscovered tunnels and a lack of documentation as to the purpose of the project has led to numerous conspiracy theories over the years. The favourite is that the tunnels were constructed to hide confiscated Nazi treasure including the famous Amber Room which disappeared from Saint Petersburg and missing gold and art from multiple locations around Europe. An area outside Wałbrzych was the focus of a story about a buried ‘Nazi gold train’ in August 2015 and today, the areas still attracts treasure hunters in search of their fortunes.

Tours & Experiences

Private Round Trip to Project Riese Including Tickets