Alcatraz Island — Cell Block D

The infamous federal penitentiary on San Francisco Bay held some of America's most dangerous criminals from 1934 to 1963. Cell 14-D in the isolation block reportedly terrifies prisoners and guards alike — a man imprisoned there in the 1940s screamed all night about a creature with glowing eyes in his cell, was found dead the next morning with no official explanation, and was seen standing in the lineup the following day before vanishing from the count. Rangers report the sound of banjos in the shower room — Al Capone, who played banjo in the prison band, remains one of Alcatraz's most active spirits.