Short of falling ill, the way into the Ospedale del Ceppo is to burrow beneath it. You’ll learn about the hospital, founded in 1277 and the city’s main hospital through the days of the Black Death (and still operating), as you follow the bed of a now-dry stream that once coursed beneath the complex and powered an olive press and simultaneously served as a laundry and source of drinking water. Tours, sometimes available in English, end at the tiny, frescoed teaching and autopsy theater built in the 1700s.