No.1 must see, Milano Cathedral

I highly recommend a 2 hour guided tour (easy to book via Trip.com) to see both the roof/terrace of the Cathedral and the inside. A local guide can give you those little stories and insights that truly elevate your visit, such as the statue of the saint who was skinned alive and whose statue is therefore moved into the back of the cathedral as to not scare people off at the entrance. Highly recommend!