Crowded most of the time and there is huge line to go inside. Everything is in order. So if you…read moredon't like to stay in the line, then i'd suggest to come as early as possible then the chances of finding the line to be short will be higher. The number of stairs going up can be a lot and the workout of going up and down can be quite intensive. If you are faint on heart, then you may have to take proper precautions and bring drinks to stay hydrated. They don't allow backpacks into the Duomo, so you may have to leave it to the backpack check in location. The view is majestic and the architecture is full of details and its surprising that it was done centuries ago... Definitely worth coming to this place!