Once Hitler seizes power in 1933 he transforms his Alpine retreat in the sleepy district of Obersalzberg in Bavaria into a vast mansion called the Berghof. The area becomes a magnet for the most powerful Nazis and Hitler's Berghof a show piece for the Reich. Aided by his most trusted assistant Martin Bormann, Obersalzberg is quickly transformed into Hitler's own fortified fiefdom. It becomes home to 2,000 SS troops and is protected by a high level security system. High above the Berghof, on top of the 6000ft Kehlstein mountain, Bormann builds the Eagles Nest; a lavish tea house designed for Hitler to entertain guests and dignitaries. Within the safety of Obersalzberg Hitler's self-belief grows out of all proportion and he becomes increasingly detached from reality. And it is in his beloved Berghof, surrounded by breathtaking scenery, that he masterminds the ugliest plans in history. But as Hitler's war collapses and the Allied bombers increase their range Obersalzberg comes under threat. Bormann increases defences around Obersalzberg but also goes deep underground. Anti-aircraft guns are placed on the surrounding peaks and a five mile labyrinth of bunkers and tunnels are dug out beneath Obersalzberg - linking the Berghof and the houses of Hitler's elite inner circle. They are fully equipped to allow Hitler to run the country even if under attack. But for the last six months of the war Hitler is far from the safe refuge of Obersalzberg. As the Red Army closes in on Berlin he is holed up in his bunker there. He chooses not to run for the safety of his Alpine retreat. On April 25th 1945 the RAF bombard Obersalzberg obliterating it but those in the bunkers mostly survive unscathed. The Eagles Nest remains intact and still stands today as a reminder of the power Obersalzberg once held.