Milan's Santa Maria delle Grazie (da Vinci) (3,4,6)

I believe the answer is:

the last supper

(Other definitions for the last supper that I've seen before include "Famous Milan mural" , "Leonardo da Vinci mural in Milan" , "Leonardo da Vinci's mural in Milan" , "Leonardo da Vinci painting in Milan" .)

I've seen this clue in the Newsday.

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