The Gratiot Union Military Prison was once located at the intersection of Eight and Gratiot.  Before the Civil War the building was used as a medical school and was somewhat was notorious for purchasing freshly dug up corpses from body snatchers.  After the war the building was left to ruin and rumored to be haunted.  The building was demolished in 1878.  The prison housed some of the most dangerous prisoners of the Civil War.  Today the site of the old prison is now the Ralston Purina Corporate Parking Lot.  Employees of Ralston Purina have claimed to have seen Confederate prisoners wondering the parking lot at night.