He made it his home, his retreat, his sanctuary. The Obersalzberg was an ordinary Bavarian mountain until Adolf Hitler discovered it in 1923. "Up on top", 700 kilometers from Berlin, the Nazi leader spent a quarter of his reign surrounded by his most faithful lieutenants and his mistress Eva Braun. At the center of the ultra-secure compound stood his immense house: the Berghof. And above that, perched on a rocky peak at 1,800 meters, the famous "Eagles' Nest" dominated the region, symbolizing their thirst for grandeur. Here, overlooking a breathtakingly beautiful landscape, the darkest ideas of humanity were conceived. But on the site, despite the bombings and the will to make the past disappear, there are some remnants. Through field studies, survivors' stories and computer-generated imagery, we will discover how a quiet little mountain was transformed into a gigantic military-political complex. 70 years after the end of the war, what are the Obersalzberg's trees hiding? What remains of the network of tunnels and the sprawling bunker system dug inside the mountain? How does history live on in every corner of Adolf Hitler's old Alpine landmark?