The refectory of Santa Maria delle Grazie Dominican convent, next to the homonym church, preserves one of the world's most famous paintings: Leonardo Da Vinci's Last Supper.

The work was realized on the north wall of the big hall between the year 1494 and 1498 during Ludovico il Moro's seigniory. It was painted by Leonardo using a “dry” technique instead of the fresco technique which was traditionally adopted for wall paintings.

The accomplishment, the environmental conditions and historical events determined a serious deterioration of the work over the centuries, and this was documented since a fewest  years from the conclusion of the work itself. Several restorations followed over the years and the last one, concluded in the year 1999 and carried out with the most advanced and the newest scientific techniques, has recovered the original paintings and they have removed, where possible, those laid up by all the interventions.

The preservation of Leonardo's work requires the best environmental conditions reached through air-tratment and through special procedures for the visitors' admission. The entrance is organized in groups of 25 people every 15 minutes.