I saw Leonardo da Vinci's painting Il Cenacolo in 1972. Fresh out of high school and wandering Europe, I was in Milano, Italy primarily to see Michaelangelo's Rondanini Pieta. A friend had told me to be sure to travel outside of the city to Santa Maria delle Grazie to view the Supper. It was interesting to see, but what was of more interest to me was that twice during wartime over the life of the painting, three of the four walls of the monastic lunchroom had been bombed away, leaving only the wall on which is painted the Supper. Is the painting divinely protected? I wondered.
Today, one has to go through a special decontamination chamber to view the painting. The chamber sucks much of the pollution from clothing. There has been for many years a concern that the painting will not be able to survive much longer. What bombs could not destroy, modern day pollution may well accomplish.
The world's largest digital photograph has recently been completed, featuring daVinci's painting. You can "interact" with it at this site. Be sure to navigate to the "Understand" page, where there is much to amaze.
DaVinci painted the Supper, which depicts the point during the Passover meal when Jesus outs Judas, for the monks to meditate on during their lunch. Seriously, there would be in my mind a concern for indigestion! Whilst supping on black bread and lentils, one can meditate on the blackest most dastardly deed in history. Or on one's own sins, for which Christ died.