Leonardo da Vinci’s Mona Lisa has sparked countless theories—from the well-established to the far-fetched. But a set of 16th- and 17th-century copies, scattered in collections from Russia to Spain, complicate the mystery of the world’s most famous painting. Art historian Laura Morelli opens the strange and wondrous world of these "other Mona Lisas, " which have made collectors, museum professionals, and art historians question everything they think they know about the world's most famous portrait. (World Art History Certificate elective, 1/2 credit)