Florence, Colorado, America

Colorado was once known for the beauty of the Rocky Mountains but today it is more famous for its Supermax prison.

Built in 1994 as a reaction to the killing of several prison guards in Illinois, the ADX houses some of America's worst criminals, notably terrorists and Mexican mafia.

Prisoners are kept in solitary confinement for 22-23 hours a day and most eat, exercise and pray alone. This is hardly surprising given that over 20% of prisoners have killed another inmate while in jail and 30% have attacked prison officers.