Located on an island in San Francisco Bay, Alcatraz was believed to be escapeproof and therefore housed some of America’s most dangerous criminals. At the time of the escape, Frank Morris was serving a sentence for armed robbery, while Clarence Anglin and his brother John were bank robbers who had been moved to Alcatraz after repeated attempts to escape from Atlanta Penitentiary.

In December 1961 the three men, who knew each other from previous incarcerations in Florida and Georgia, were allocated adjacent cells. For the next few months they, and fellow inmate Allen West, widened the ventilation ducts in their cells using makeshift tools in order to access an unguarded utility corridor. Here they fashioned life preservers, a rubber raft, and paddles. Meanwhile they used dummy heads made of concrete dust, toothpaste, soap, and real hair to fool the prison guards. The heads were placed in their beds to make it appear as though they were sleeping.

On the night of 11 June the inmates accessed the roof from the utility corridor from where they descended to the ground, although West was unable to get through the ventilation duct to join them. Once outside the prison walls, the three men inflated their raft with a modified accordion and launched it into San Francisco Bay.

Prison authorities discovered the empty cells the next day and launched a massive manhunt for the escapees. Despite an extensive search, no trace of the inmates was ever found. The fate of Morris and the Anglin brothers remains unknown to this day and, although the FBI believes they drowned in the treacherous waters of the bay, their possible survival continues to inspire debate.