S1, E3: Berlin, Germany was the battlefield of the 20th century. And today, sealed up and forgotten beneath its streets are remnants of this dark past. Walk anywhere in the city and you could be walking directly on top of one of the over 1000 Nazi bunkers engineered into Berlin's sandy soil, lost remnants of Hitler's ill-fated Germania or even beer brewing plants that inspired the Nazis' journey into the underground. Join host Eric Geller as he travels through the dark and damp recesses of Berlin's secretive soil. We're peeling back the layers of time on Cities of the Underworld: Hitler's Underground Lair.