The Last Supper (da Vinci, 1498)

Commissioned by Ludovico Sforza, Duke of Milan, and completed in 1498, Leonardo da Vinci's The Last Supper covers a 460 x 880 cm wall in the refectory of the Convent of Santa Maria delle Grazie in Milan. Unlike most Renaissance fresco artists, Leonardo experimented with tempera and oil on a plaster base, causing the painting to deteriorate almost immediately — it has undergone 20 major restoration campaigns since the 17th century. It has been copied more than any other painting in history and remains a UNESCO World Heritage Site.