This is the door and main entrance of the Florence Cathedral more commonly known as the Duomo. It is one of Italy's largest churches, and until development of new structural materials in the modern era, the dome was the largest in the world. It is till the largest brick dome ever constructed.
This door was made by the Italian sculptor Augusto Passaglia and is made out of brass.
The details on this door and the color inlays and intricate sculptures on, in and round the rest of the Duomo make it an amazing sit to behold. If you are planning a trip to Italy, A visit to Florence to see the Duomo and Michelangelo's David is highly recommended.