In a dense forest in former East Prussia, the easternmost province of the German Reich until the end of World War II, Adolf Hitlerbuilt his secretive Wolf’s Lair (Wolfsschanze) military headquarters. Located near the small town of Ketrzyn in Poland, the hermetically sealed and highly guarded complex was built between 1940 and 1944 and included 50 bunkers, 70 barracks, two airfields and a railroad station. Hitler, his secretary Martin Bormann and Reichsmarschall Hermann Göring had private bunkers, and one was reserved for state guests. The walls of the concrete structures were between five and seven meters thick. Three heavily secured...