The Dock: Seven Prisons

Inside an Alcatraz prison cell.

Dan Friedman NPS

Imagine being locked in a steel and concrete box for 23 hours per day. What would you do to stay sane? Today, all of the 400 prisoners at ADX in Florence, Colorado, the Alcatraz of the Rockies, are held in solitary confinement, and many are there for decades or even life. US Penitentiary Alcatraz Island, which operated from 1934-1963, was not as strict as ADX, yet it was a formidable place. The penitentiary was actually the last of six different prisons on the island dating back to 1859.