Delve into the underbelly of subterranean Pisa with a one-hour guided trek (in English) of passageways snaking beneath 13th-century hospital Ospedale del Ceppo, famed for its colourful Della Robbia ceramics on Piazza Giovanni XXIII.
The dark, dank, barrel-vaulted tunnels follow the course of a subterranean river, diverted underground in the 13th century in order for the hospital above ground to increase in size and so care for Black Death victims. The passageways later served as a laundry, oil mill and public grain mill powered by the underground river. Not recommended for the claustrophobic.