The Duomo of Como is found downtown, near Lake Como Nord station and the pier where you catch the ferry to visit the villages of Lake Como. It's a lively town square, with many terraces and restaurants. We decided to visit as we left our ferry. Outside, it's a very beautiful cathedral with a wonderful blue cupola. The interior is also very nice, but rather dark. It's a pity that the central altar was being restored when we visited, and the whole area was covered up. I noticed that there were several people continuously mopping the floor of the cathedral. Admission is free. Of course, you can't enter with shorts or strapless clothes.