Fodor's Expert Review Museo delle Terme di Diocleziano

Though part of this ancient bath complex (the largest in the Roman world) is now the church of Santa Maria degli Angeli, and other parts were transformed into a Carthusian monastery or razed to make room for later urban development, a visit still gives you a sense of the scale and grandeur of this complex, which included a gymnasium, library, and public baths. Upon entering the church, you see the major structures of the baths, partly covered by 16th- and 17th-century overlay, some of which is by Michelangelo. The calm monastery cloister is filled with the Museo Nazionale Romano's collection of inscriptions; other rooms have pieces associated especially with remote Roman antiquity (think: huts), as well as archaeological finds from Rome's Republican and imperial periods, including a rare painted relief of the god Mithras.