Two human skeletons wrapped in a complete network of arteries and veins sit behind glass under a chapel in Naples.
They were displayed in the palace of Raimondo di Sangro, Prince of Sansevero, until his death in 1771, then moved to the chapel basement where visitors still see them. Nobody knows exactly how the vessels were preserved. In The Italian Test, that open question becomes the anatomist Giuseppe Salerno and a private notebook he never shared with his prince.