The United States Penitentiary, Administrative Maximum Facility (USP Florence ADMAX), commonly known as ADX Florence or Supermax, is an American federal prison in Fremont County near Florence, Colorado, operated by the Federal Bureau of Prisons, a division of the United States Department of Justice. ADX Florence, constructed in 1994 and opened one year later, is classed as a supermax or “control unit” prison, thus providing a higher, more controlled level of custody than a maximum security prison (or “high security,” as it is called in the federal prison system). ADX Florence forms part of the Federal Correctional Complex, Florence (FCC Florence), which is situated on 49 acres (20 hectares) of land and houses different facilities with varying degrees of security, including the adjacent United States Penitentiary, Florence High. ADX Florence was commissioned when the Federal Bureau of Prisons needed a unit designed specifically for the secure housing of those prisoners most capable of extreme violence toward staff or other inmates, as well as inmates deemed too high-profile or too great of a security risk for even a maximum security prison. The inmates are confined for most of the day in single cells with facilities made of poured, reinforced concrete to deter self-harm, and are under 24-hour supervision, carried out intensively with high staff–inmate ratio