Alcatraz Citadel having some 111 cannons encircling the island at peak, and was also used as a war camp. During the Civil War, the defense establishment at Alcatraz Citadel had the onerous task to defuse the possibility of any local war between the Union and Confederate supporters who were both part of the population of California, and to protect San Francisco. Ammunition in the form of 10,000 muskets and 150,000 cartridges was supplied to the fort, which made the Fort Alcatraz and the island most impregnable and thus leaving any plans of the Confederate soldiers of taking control of the San Francisco
Alcatraz Federal Penitentiary legendary prison" suited to the times, which resulted in the Alcatraz Island Federal Penitentiary being nicknamed "Uncle Sam's Devil's Island." Despite Alcatraz being designed to house the "worst of the worst" of criminals who caused problems at other prisons, under the guidelines and regulations set by the strict prison administrators, courts could not direct a prisoner to be directly sent to Alcatraz, however notorious they were for misbehavior and attempted escape from other prisons. Prisoners entering Alcatraz would undergo vigorous research and assessments prior to their arrival. Security in the prison was very tight, with the constant checking of bars,