The historic Duomo di Milano is the largest cathedral in Italy (and the 5th largest in the world).
The Duomo Milano is a truly amazing wonder of an example of what humans are capable of creating – grounded in 1386 and not completed before 1965.
An obscenely amount of architects has been involved during these more than 600 years. Unfortunately we did not get to go inside this time since the queue was something like a mile long. But you can go inside, and you can also have a guided tour around the top of the cathedral. On my bucket list for next visit to Milan for sure.