Authorities were alerted to the fire after a smoke detector triggered an alarm about 9.50pm Friday local time, police said.
No potential cause was given, but German media reported that investigators suspected arson.
As snow fell on the alpine peak, the Eagle’s Nest was still engulfed in flames on Saturday, a weather camera showed.
Monument to Hitler
Officers blocked access to the road leading to the retreat, an AFP photographer saw. Firefighters found no one inside the building.
Maier said the investigation was ongoing. Police have planned a news conference later on Saturday.
German tabloid Bild reported that authorities arrested a motorcyclist they came across on their way to the scene.
Built between 1937 and 1938, the Eagle’s Nest forms part of the toxic legacy of Hitler’s Third Reich, which was responsible for the deaths of millions of Jews, along with Roma, LGBTQ people and Communists, in the Holocaust.
It was designed to serve as a monument to Hitler’s rule, though the dictator himself rarely visited the complex. Built of stone and granite, the residence offers an exceptional view of the picturesque Bavarian alpine landscape and was designed to impress foreign diplomats.
It survived World War II undamaged. Since 1952, it has hosted an exhibition recounting the house’s Nazi history and a restaurant.
– AFP