The Missouri State Penitentiary was nicknamed 'the bloodiest 47 acres in America' by Time magazine in 1967 due to the numerous violent deaths and brutal assaults that took place there. The prison dates back to the early 1800's and housed some of America's most violent criminals before becoming decommissioned in 2004.
In 2009 the prison opened its doors to the public offering tours of the site. Since then, reports of disembodied voices, apparitions, and sounds of slamming cell doors have been made. Back in June, the team from TAPS came to the penitentiary to investigate the claims of paranormal activity there. An upcoming episode of Ghost Hunters will air their findings in November.
I have not found a whole lot of information regarding the unexplained occurrences claimed to be going on here. However, I did come across a disturbing article from a former inmate called The Wall. I am looking forward to seeing what TAPS found, if anything, during their investigation.