When Milanese think something is taking too long, they refer to it as la fabbrica del duomo -- the making of the Duomo, a reference to the 5 centuries it took to complete the magnificent Gothic cathedral that rises from the center of the city. (This turn of phrase could also describe the church's recent 6-year renovation, which kept the building behind scaffolding until 2009.) The last of Italy's great Gothic structures -- begun by the ruling Visconti family in 1386 -- is the fourth-largest church in the world (after St. Peter's in Rome, Seville's cathedral, and a new one on the Ivory Coast), with 135 marble spires, a stunning triangular facade, and 3,400-some statues flanking the massive but airy, almost fanciful exterior.

The cavernous interior, lit by brilliant stained-glass windows, seats 40,000 but is unusually spartan and serene, divided into five aisles by a sea of 52 columns. The poet Shelley used to sit and read Dante here amid monuments that include a gruesomely graphic statue of St. Bartholomew Flayed and the tombs of Giacomo de Medici, two Visconti, and many cardinals and archbishops. Another British visitor, Alfred, Lord Tennyson, rhapsodized about the view of the Alps from the roof (elevators on the church's exterior northeast corner; stairs on the exterior north side), where you get to wander amid the Gothic pinnacles, saintly statues, and flying buttresses. You are joined high above Milan by the spire-top gold statue of Madonnina (the little Madonna), the city's beloved protectress.

Back on terra firma, the crypt contains the remains of San Carlo Borromeo, one of the early cardinals of Milan. A far more interesting descent is the one down the staircase to the right of the main entrance to the Battistero Paleocristiano, the ruins of a 4th-century baptistery believed to be where Saint Ambrose baptized Saint Augustine.

The Duomo houses many of its treasures across the piazza from the right transept in the Museo del Duomo section of Milan's Palazzo Reale -- closed for restoration in 2009 without a definite reopening date. Among the legions of statuary saints is a gem of a painting by Jacopo Tintoretto, Christ at the Temple, and some riveting displays chronicling the construction of the cathedral. Adjoining this is the Museo Civico d'Arte Contemporanea (Civic Museum of Contemporary Art), with works by living artists and such masters as De Chirico and Modigliani.

Though the scaffolding from its most recent restoration is down, visitors may still encounter some restoration work. The most recent restoration, completed in 2009, brought luster back to the church's white marble. Other restoration projects will continue on the sides and interior of the Duomo in a never-ending bid to keep the building looking its best.