This converted cloister is best known for the collection of models based on Leonardo da Vinci's sketches (although these are not captioned in English, the labeling in many other exhibits is bilingual). On the ground level, in the hallway between the courtyards, is a room featuring interactive, moving models of the famous vita aerea (aerial screw) and ala battente (beating wing), thought to be forerunners of the modern helicopter and airplane, respectively.
The museum also houses a varied collection of industrial artifacts including trains, a celebrated Italian-built submarine, and several reconstructed workshops including a watchmaker's, a lute maker's, and an antique pharmacy. Displays also illustrate papermaking and metal founding, which were fundamental to Milan's—and the world's—economic growth. There's a bookshop and a bar. Avoid this museum on weekends. It's a popular spot for families, and there are long lines on those days.