The Cenacolo di Sant'Apollonia contains Andrea del Castagno's fresco of the Last Supper, painted around 1447 for the nuns of the Benedictine convent of Sant'Apollonia. It is one of the earliest painted Last Suppers in Florence, predating Leonardo's famous version in Milan by nearly fifty years, and it achieves a dramatic psychological intensity through Castagno's stark, angular figures and the bold use of a fictive marble inlay ceiling.
What makes this site remarkable is how few visitors find it. The entrance is on a quiet street near the university, the museum is free, and on any given weekday you may have the large refectory entirely to yourself. The room also contains three other detached frescoes by Castagno — the Resurrection, the Entombment, and the Pietà — which were painted above the Last Supper and are displayed on the opposite wall. The Florentine state museums system runs the cenacolo, and opening hours are limited (typically Tuesday to Saturday, check current hours before visiting).