Built in the early 20th century as a tuberculosis hospital, the Mount Parnitha Sanatorium later served as a psychiatric asylum before being abandoned in the 1980s. Now in ruins, it is considered one of Greece’s most haunted sites, with visitors reporting shadowy figures moving through the crumbling wards, sudden drops in temperature, and whispers carried along the mountain winds. Paranormal enthusiasts flock here, drawn by its eerie history and the unsettling atmosphere that lingers long after nightfall.