Originally built in 1898 as a sprawling tuberculosis sanatorium, this 60-building complex served as a massive military hospital during both World Wars, famously treating a young Adolf Hitler in 1916 and later serving as the largest Soviet military hospital outside the USSR until 1994. The site is shrouded in a dark history of real-world horror, including the “Beast of Beelitz” serial killings and a 2008 ritualistic murder in the abandoned operating theater, fueling widespread reports of “zombies” and spectral soldiers wandering the decaying corridors. Modern visitors, often viewing the ruins from the “Baum und Zeit” canopy walkway, report disembodied screams, phantom footsteps, and a heavy, oppressive atmosphere that permeates the skeletal buildings. Despite ongoing redevelopment and its use as a set for films like The Pianist and A Cure for Wellness, the “Alpenhaus” with its rooftop forest remains a primary hotspot for sightings of shadow figures and flickering lights in the windows.