First insight into the underworld of the Obersalzberg. Between 1923 and 1945, the Obersalzberg transformed from a peaceful mountain idyll into a cult site of National Socialism and ultimately into the Führer's headquarters. For twenty years, Hitler's catastrophic decisions and orders were conceived there. The effects and wounds of those decisions continue to resonate worldwide to this day. As the Third Reich was in decline, preparations were made at the Obersalzberg for an escape into the depths. Starting in 1943, a vast bunker system was created to allow Adolf Hitler to continue governing underground. Over five kilometers of tunnels and shafts were painstakingly carved out of the mountain. By mid-1944, the secret Führer headquarters was operational, and the government had moved in. Just a few months later, the Obersalzberg was hit by nearly four hundred British bombers in a dramatic large-scale attack.