Triple murderer Thomas Silverstein was one of the most dangerous men in America.
The white supremacist butchered a fellow inmate who had refused to act as a heroin mule while he was serving 19 years for armed robbery.
Just a year later, in 1981, he was accused of murdering Robert Chappelle, another fellow prisoner and member of the DC Blacks gang.
While he was on trial, the national leader of the DC Blacks gang, Raymond Smith, was transferred to his prison and logs show he immediately started plots to kill Silverstein.
So he and another prisoner, Clayton Fountain, stabbed him with improvised weapons 67 times and dragged Smith's body up and down the walkway in front of cells packed with lags.
Then, two years later, Silverstein carried out his final murder of Correction Officer Merle Clutts, stabbing him dozens of times.
Now serving three life sentences, the former leader of the Aryan Brotherhood, was placed in solitary confinement for the next 35 years with one strict instruction - "no human contact".
And when the United States Penitentiary, Administrative Maximum Facility (USP Florence ADMAX) opened in 1994, Silverstein was on of the first inmates to be moved there.
The Supermax prison in Florence, Colorado, is so secure it has been dubbed the 'Alcatraz of the Rockies'.
There Silverstein spent the rest of his life, confined alone in his soundproof cell, which had the lights on 24 hours a day.
The 67-year-old died of complications from a heart condition on May 11.
Phones are banned in the 'Alcatraz of the Rockies' and prisoners in the are kept in their cells for 23 hours a day.
Each cell is made almost entirely from concrete, includng the desk, stool and bed.
Showers only run on timers and all the lights are remote controlled.
All the cells are soundproof to prevent prisoners from communicating with each other by Morse code.
Exercise is in a concrete pit. They can only walk 10 steps in a straight line, or 31 in a circle.
Within the walls of the prison there ae 1,400 remote controlled steel doors, which can all be instantly closed with one press of the panic button by one of the guards.
Heavily armed guards are in constant patrol around the 12 foot razor wire fences that surround the Supermax jail.
Three Z-unit cells exist for prisoners deemed to be an extreme security risk.
In these ull body restraints are fitted to the concrete beds.
But each of these extreme security precautions are needed as the 'Alcatraz of the Rockies' houses some of the world's most dangerous men.
Zacarias Moussaoui - terrorist who played a key role in the 9/11 attacks
The 50-year-old is serving six life sentences without the possibility of parole for his role in the atrocities.
He was origainally arrested in August 2001 and charged with an immigation violation after authorities bcame suspicious about the flight training courses he had been taking.
Moussaoui pleaded guilty to terrorism charges in 2005.
The jury could not reach a unanimous verdict needed for the death penalty to be imposed and instead must spend his sentence in the Supermax prison.
Richard Reid - British shoe bomber
Borm in Bromley, London, 45-year-old Reid converted to Islam while he was serving time for petty crimes in the UK.
On his release he travelled to Pakistan and Afghanistan and became radicalised.
Joining al-Qaeda, Red tried to blow up a bomb on a flight from Paris to Miami in 2001.
He had concealed the device in his shoe ut was subdued by fellow passengers.
Reid pleaded guilty to all charges and was sentenced to thtree life sentences, plus 110 years.
Dzhokhar Tsarnaev - Boston Marathon bomber
Tsarnaev was convicted, along with his brother, of planting the pressure cooker bombs at the Boston Marathon in April, 2013.
The blasts killed three poeple and injured more than 280 others.
Then a student, Tsarnaev, went on the run but was arrested four days later when he was found, severely wounded and hiding in a boat.
He was conviced in April, 2015, and sentenced to death on June 24 of the same year.
But before his executon the 25-year-old is being kept in the ADX jail.
Theodore Kaczynski - The Unabomber
Kaczynski carried out a mail bombing campaign between 1978 and 1995.
He carried out 16 bombings, which killed three and injured 23.
The 77-year-old targeted companies and people connected to modern technology.
He will serve his life in prison, without the possibility of parole.
Abu Hamza al-Masri- Extradited from the UK in 2012
Abu hamza was the former imam of Finsbury Park Moque in London, where he tried to radicalise those who worshipped there through his preaching.
Born in Egypt, he came to Britain to study in 1979 and was radicalised 20 years later.
With only one eye and no arms. Abu Hamza often used a hook instead of his limb.
He was arrested in Britain in 2004 while the extradition process took place.
Hamza was convicted of terrorism charges in the UK and was extradited to the US in 2012.
He stood trial for 11 counts, ncluding taking 16 hostages in Yemen in 1998, urging jihad in 2001, supporting the foundation of a terrorism training camp and helping al-Qaeda.
Hamza was found guilty of all the terrorism charges and sentenced to spend the rest of his life at ADX Florence.
Anthony Casso - Mobster and boss of the Lucchese crime family
He admitted carrying out 36 murders but police believe he may be responsible for many more.
Despite turning informer, this was later rescinded after he breached its conditions and Casso was sentenced to 455 years in prison.
He was initially jailed at ADX Florence but was transferred to a medica facility when he was diagnosed with cancer in 2009.
Casso is now serving his sentenced in a medical prison in Missouri.
