Holding about eight million human bones, the ghoulish Fontanelle Cemetery was first used during the 1656 plague, before becoming Naples' main burial site during the 1837 cholera epidemic. At the end of the 19th century it became a hot spot for the anime pezzentelle (poor souls) cult, in which locals adopted skulls and prayed for their souls. Lack of information at the site makes joining a tour much more rewarding; reputable outfits include Cooperativa Sociale Onlus 'La Paranza'.
Avoid guides offering tours at the entrance.