The buildings of the archeological museum are as interesting as the collections within. The initial courtyard was once the entrance to the Monastero Maggiore; and a detailed model, just past the museum's reception, shows Milan's Roman incarnation as Mediolanum.
Indeed, almost the entire ground floor is dedicated to artefacts from the important settlement Mediolanum, including the unique Coppa Trivulzio Diatreta from the late fourth century, a cup created from a single piece of glass, and the wonderful stone Zeus head from the first or second century. The impressive prehistoric section covers the Milan area from the Neolithic period to Roman times.
Downstairs you'll find a stretch of Roman city walls (built under Emperor Maximian in the third century) and an area (newly refurbished in 2008) containing a small selection of Greek artefacts. There's also a surprisingly extensive collection of Buddhist art from the ancient kingdom of Gandhara (now northern Pakistan and eastern Afghanistan), bought by the museum in the 1980s.
The gardens at the rear hold a polygonal tower, originally part of the city's defence system; later, it was transformed into a chapel for the monastery. The round interior is decorated with 13th-century frescoes, including a vivid image of Jesus beaming his stigmata through the air to St Francis of Assisi.