Canals that were built around the 12th century as a water transport system are now the focal point for a popular, exciting neighborhood in Milan. Take the green metro line all the way down almost to the end, Porta Genova. You'll find narrow streets opening up onto one main canal (Naviglio Grande), along which are great restaurants, nightclubs, cafes, and shops. The Naviglio area is home to a lot of young people (more of the students at my university lived here) and it hosts many events like markets, art fairs, and outdoor concerts. It has a very alive, energetic atmosphere and is particularly popular during the warm months. On the weekends people literally spill out of every public place and the sidewalks and little bridges are crowded. A couple of my favorite places are Pizzera Fabbrica and Le Schimmie, a legendary live jazz music club.