Pistoia's star outdoor attraction is the facade of the Ospedale del Ceppo, one of the best works by the often disappointing Giovanni della Robbia and Pistoia's answer to the Ospedale degli Innocenti in Florence, which was decorated by Giovanni's father, Andrea. Here, Giovanni was in top form, creating a frieze (1514-25) of glazed terra-cotta panels to surmount a Michelozzo-designed loggia. The six well-preserved della Robbia panels, plus a decaying one added later by Filippo Paladini, represent the seven acts of mercy, divided by the cardinal and theological virtues.

The hospital is also the jumping-off point for the Pistoia Sotterranea tour, inaugurated in mid-2010. The 1-hour guided visit follows the path of a diverted stream, under a couple of intact bridges now below the hospital's foundations, that over the centuries has served as a power source for an olive press, a public laundry, a refuse dump, and a source of water -- often simultaneously. The fascinating tour takes in the history of the hospital above (founded in 1277 and still going strong), and ends at the tiny, frescoed teaching and autopsy theater that was built in the mid-1700s and used to teach medical students until its replacement by the Medical Academy in 1844. Tours in English are available.