Santa Maria Della Concezione Dei Cappuccini Church

The church is most famous as an ossuary, known as the Capuchin Crypt, in which is displayed the bones over 4,000 Capuchin friars, collected between the years 1528 and 1870. The bones are fashioned into decorative displays in the Baroque and Rococo style. The popularity the crypt as a tourist attraction once rivalled the Catacombs. The Sedlec ossuary (1870) in the Czech Republic is said to have been inspired from it.
Literary references
Several renowned authors visited the crypt and left descriptions. The Marquis de Sade, who visited the crypt in 1775, wrote, “I have never seen anything more striking” (Voyage d'Italie, p. 106 the Maurice Lever edition). Mark Twain visited the crypt in the summer 1867, and begins Chapter XXVIII The Innocents Abroad with 5 pages his observations. Nathaniel Hawthorne describes the crypt in his novel The Marble Faun. Additional descriptions were written by authors Tom Weil (1992), Folke Henschen (1965) and Anneli Rufus (1999). You can check Christine Quigley, Skulls and Skeletons, pp. 175–176.