Kamienna Góra
Thought to contain many secrets including which people were traitors during the war, the archive thought to be inside the Bond-like underworld complex has been described as ‘an invaluable source of information about the dark times of the WWII occupation.’
Association of Lovers of Upper Lusatia
Nazi tunnels inside inactive VOLCANO could hide long-lost archive of Kraków Gestapo, say explorers
