Jay Y.
Yelp
People are willing to line up to enter the Duomo and even climb the Dome, but very little people know that the true treasures lie near them. Here's a little secret: some of the stuff you see on the outside, including the Baptistery's bronze Door of Paradise, are replicas and the original are stored for better preservation in this often-ignored museum! If you want to see more about the Duomo and truly appreciate this architectural splendor even more, you cannot miss this museum.
Newly renovated, Museo dell'Opera del Duomo is indeed a world-class museum worthy of the Duomo that it exhibits. Here, you will find all the original statues of the facade, the Door of Paradise, and many things that are no longer in the Duomo such as the removed choir gallery! Better yet, you will also find precious relics such as St John the Baptist's jawbones and significant artworks like Michelangelo's "Florence Pieta"
This museum is well-organized and modernized, and has many interesting and engaging explanations to give you a better understanding of the many aspects of the Duomo such as its history and its construction process. While the Duomo is already impressive at first sight even without knowing a thing about it, I guarantee that you will love the Duomo more after learning about why you should be even more impressed with this symbol of Italian Renaissance.
Besides, you already paid a €15 combined admission for the Duomo complex, so if you are already visiting the Duomo, you cannot miss this museum!
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tl;dr version:
1) Often-ignored museum that is the true treasure of the Duomo complex
2) Houses many originals like the Baptistery's Door of Paradise and other artworks
3) Well-organized, modernized museum that aims to engage and should not be missed!