An exceptionally large and elaborate Gothic cathedral on the main square of Milan, the Duomo di Milano is one of the most famous buildings in Europe. It is the largest Gothic cathedral and the second largest Catholic cathedral in the world. The street plan of Milan, with streets either radiating from the Duomo or circling it, indicates that the Duomo occupied the most important site in the ancient Roman city of Mediolanum. Saint Ambrose built a new basilica on this site at the beginning of the 5th century, with an adjoining basilica added in 836. When fire damaged both buildings in 1075, they were rebuilt as the Duomo