This is a pedestrian path running for almost 24 miles along the Naviglio Maresana (river), connecting Milan with the Adda river. This path is well known among local runners, especially those training for a marathon, as it offers runners an uninterrupted off-road path surrounded by greenery. There are ancient villas and other unexpected beauties long the route. One can certainly do any portion of the 24 miles, especially since the path starts in central Milan. The path is especially pretty in spring, with lots of blooming flowers and plants. Note that the Naviglio Martesana runs parallel to the M2 line, which makes it easy to run one way and hop the train back.