ruins of old german bunkers at woolf's liar

barbarossa europe german gierloz hitler ketrzyn masurian poland prussia rastenburg stauffenberg valkyrie wolfsschanze woolf liar architecture attraction bunker camoulfage demolition forest fortifications guest headquarter hidden history landscape military network outdoor plan protected secret war 39aph39 partly preserved old middle rut ruins bunkers 039 adolf abandoned upside concrete hide forgotten industrial moss structure attempt assassination shade shady