The Last Supper/Il Cenacolo/Santa Maria delle Grazie
Despite Leonardo's carefully preserved preparatory sketches, in which the apostles are clearly labeled by name, there still remains some small debate about a few identities in the final arrangement. There can be no mistaking Judas, however—small and dark, isolated from the terrible confusion that has taken the hearts of the others. Reservations are required to view the work. Viewings are in 15-minute timed-entry slots, and visitors must arrive 30 minutes before. Reservations can be made online. Reserve at least three weeks ahead if you want a Saturday slot, two weeks for a weekday slot. Some city bus tours include a visit in their regular circuit, which may be a good option.