Dominating the central square, Duomo is the world's largest Gothic cathedral, with 135 spires sprouting from the roof. Climb up among the 2300 statues adorning its façade for views of Milan. Inside, marble-patterned floors and decorative stained-glass windows impress visitors.
The Duomo was started in 1386 and finished in 1887, taking more than 500 years to build. The marble building boasts Europe's largest sundial. Five enormous naves separated by finely worked stone pillars are framed by a series of beautifully worked stained-glass windows. The apse is the oldest part of the church, where three rose windows designed by Filippino de Modena reveal the complexity of the 14th-century stonework.
Features to keep an eye out for include Perego's Madonnina, the neoclassical central bronze doors designed in 1906, and make sure you catch a glimpse of the Duomo's most holy relic - a nail from Christ's cross, housed inside a large crucifix which hangs suspended above the chancel. Once a year, on the Feast of the Cross, it is the focus for an extraordinary ceremony.
Clamber up to the roof terraces to examine the Duomo's spires and statues while enjoying a breathtaking view of Milan and, on a clear day, the snow-capped mountains of the Bergamo Alps.