The most important industrial area of the region for the large presence of factories. Until the early XIX century, Sesto San Giovanni was just a small rural farming village, but with the road reorganization of the area, its quick access to the Northern passes, the large building possibilities and the proximity to the power plant on the Adda, it developed into one of major industrial centers of the Lombard capital. The first spinning mill was opened in 1832 by Giuseppe Puricelli Guerra in a wing of the villa of the family. The building of the first industrial plant, entirely in brick of the Campari factory, is in terms of an architectural-historical-social context, one of the most important examples for the whole Italian Industry.
The town's name derives from the distance in miles from Milan on an old Roman road ( "ad sextum lapidem", or at the sixth milestone), the second part of the name, San Giovanni, was introduced in 1100, to make clear the dependence of the territory from the Basilica of San Giovanni in Monza.

Not to miss:
- The Basilica of St. Stephen, the unfinished façade features a non decorated brick wall and empty niches, the interior has a Latin cross shape with three naves and inside the chapel of San Clemente the remains of the saint are preserved, found in the catacombs of San Callisto in Rome;
- Villa Pelucca, built in medieval times, it was altered in later centuries and features a small chapel decorated with frescoes by Luini, a pupil of Leonardo da Vinci;
- Villa Puricelli Guerra, home of the first textile mill in the city;
- Villa Visconti d'Aragona, of the XVI century, with splendid frescoed rooms, today seat of the Central Library;
- Villa Mylius, dating from the XVIII century, it was the seat of the council offices from 1921 to 1971;
- Villa Torretta, of medieval origin, today it is a luxury hotel.