Founded in 1609 to display the private collections of the pious Cardinal of Milan Federico Borromeo, this gallery is housed in the world’s second-oldest public library (after the Bodleian in Oxford, U.K.). While the emphasis is on Italian art from the 15th to early 20th centuries, some Dutch work is also exhibited.

Despite the confusing layout encompassing courtyards, passageways, stairwells, and any number of tiny exhibition rooms, the gallery is well worth visiting for four outstanding works of art: the cartoon for “The School of Athens” by Raphael (1510); Caravaggio’s charming “Basket with Fruit,” from around 1599; and Titian’s “Adoration of the Magi” (ca. 1550). The fourth, the haunting “Portrait of a Musician,” has been attributed to Leonardo da Vinci (1490), although many scholars question that provenance. If it is indeed a da Vinci, however, it’s his only painting hanging in any Italian museum.

Leonardo’s original “Codex Atlanticus” is in the Biblioteca Ambrosiana next door along with other rare manuscripts; drawings from the “Codex”, which consists of 1,750 drawings and jottings the master did between 1478 and 1519, can be seen in the Sacristy of Bramante in Santa Maria della Grazie. Leonardo’s entire life as an artist and scientist can be found in this extraordinary collection.