Palazzo della Cancelleria is a Renaissance palace near Campo de' Fiori that served for centuries as the papal chancery. Its long, controlled facade hides a grand courtyard and the Basilica of San Lorenzo in Damaso, an ancient Roman house church rebuilt into the palace complex in the 15th century.
Even when interior access is limited, the palace is worth a look while walking between Campo de' Fiori and Piazza Navona.