Duomo
The English novelist D.H. Lawrence called the Duomo " an imitation hedgehog of a cahedral", because of its pointy intricate exterior. But in side, the church is simple, majestic and vast. Milano's navel, Piazza del Duomo, has the atmosphere of London's Piccadilly Circus and much more interesting architecture. The cathedral was commissioned in 1386 and is the world's fourth-largest church. The late-Gothic wonder features a forest of spires and statuary, marble pinnacles and pillars, all woven together with a web of flying buttresses. A gilded copper statue of the Madonna rises above the myriad vertices, distracting awed observers from the church's most interesting omission: The duomo has no bell tower.

The duomo's finest relic is a nail purportedly used to pin Jesus to a cross all those years ago. Every September, the Archbishop of Milan retrieves the sacred bit of metal from its perch high above the nave and presents it to an adoring (or at least curious) congregation.
The neighboring Museo del Duomo chronicles the church's six centuries and displays an interesting collection of art and artifacts.

Cenacolo Vinciano
Leonardo da Vinci captured the Bible's most poignant moment, The Last Supper, in an experimental mix of tempera and oil. The paint has been steadily peeling from the walls of this convent since 1498. Waves of restoration have removed all but an echo of the master's brushstrokes, but that's enough. It's a powerful piece of work.
To visit the refectory of the Convento di Santa Maria delle Grazie, where the painting was most recently restored in 1999, you'll need to plan ahead. To join a group of 25 (sluiced through every 15 minutes), book weeks in advance by phone and get ready to give your credit card a workout. There are tales of travelers who managed to get in without making prior arrangements, but such miracles seem reserved for the truly faithful.

Castello Sforzesco
At the northeastern end of the lovely Via Dante, which intersects the Piazza del Duomo, looms the imposing Castello Sforzesco. Originally a military fortress, it was completely remodeled by more comfort-minded Francesco Sforza. The new and improved defenses were designed by Leonardo da Vinci.
The castle houses a collection of modern museums that are well-stocked with impressive antiquities. The excellent sculpture collection includes Michelangelo's Piet? Rondanini. There are also paintings by Bellini, Tiepolo, Mantegna, Correggio, Titian and Van Dyck. If you get bored with Italian masters, the collection of Egyptian artifacts should prove distracting.
Behind the castle, Parco Sempione is a 47-hectare (116-acre) park with plenty of places to stroll and an interesting (if a bit dilapidated) arena that was inaugurated by Napoleon.

Teatro alla Scala
Rising above Piazza della Scala (itself dominated by a monument dedicated to da Vinci) is the renowned Teatro alla Scala. La Scala, as it is commonly known, first raised its curtain in 1778 and has treated generations of opera aficionados to arias aplenty over the years.
The theater was heavily damaged by bombs during WWII, but reopened in 1946 under the baton of famed composer Arturo Toscanini, who had returned to Milan after an eight-year stint as director of the New York Philharmonic.
The adjoining Museo Teatrale alla Scala boasts such curiosities as Verdi's death mask (complete with the maestro's facial hairs).