Haunted Eastern State Penitentiary, Philadelphia, PA

The castle-like Eastern State Penitentiary took solitary confinement to new levels when it was built in 1829. Prisoners lived alone, exercised alone, and ate alone; when an inmate left his cell, a guard would cover his head with a hood so he couldn't see or be seen. 

The prison had to abandon its solitary system due to overcrowding in 1913, although the forms of punishment did not get any less severe (chaining an inmate's tongue to his wrists is one example) before it closed for good in 1970. 

The site now welcomes thousands of visitors every year. Reported paranormal happenings have included disembodied laughter, shadowy figures, and pacing footsteps.