Originally Posted by
allset2travel
If you are a history and art buff, take in the Last Supper by the Master Leonardo da Vinci, at the Santa Maria delle Grazie (go by subway).
Good suggestion, but if you do so, be sure to make a reservation ahead of your visit (to avoid the long lines, which is essental given your time window). I use the phone service, very easy and with English-speaking operators:
http://www.cenacolovinciano.it/html/eng/accoglienza.htm
The reservations are only €1,50.