The dungeons in which popes once threw enemies of their earthly power will reopen this summer for spooky night tours.
The tiny grated cells under former papal fortress Castel Sant'Angelo are clinking open again after a ten-year restoration.
Visitors will be shown into the dank, oil-lit spaces where thousands of political and common criminals were shut away in the days that the Vatican held temporal sway over Rome and much of central Italy.
Guides will recount the tales of famous inmates such as turbulent gold-working genius Benvenuti Cellini who spent months there in 1538 on charges of embezzling the papal tiara and tried a daring escape amid fears of the noose.
Heroes of the Risorgimento, the movement that eventually reunited Italy and ended the papal state, were also enclosed in the jail above Emperor Hadrian's ancient tomb - as recounted in Giacomo Puccini's famous opera Tosca.
Among the other notorious guests was Cagliostro, a Freemason and alleged occultist sent to the dungeons by the Holy Inquisition.
Inmates who met their death on the scaffold included a Roman family, the Cencis, hanged in 1599 after a shocking affair of incest, murder and revenge.
Their story - and in particular the apparent innocence of daughter Beatrice - inspired writers like Shelley, Dumas and Stendhal.
Guided tours of the prison, lasting from 21:30 to 23:10, will start on July 13 and end a month later.
