The upper facades of the two much-enlarged transepts were filled with two spectacular 12m-wide rose windows.
Unfortunately the architect was not as successful with another material, the white marble he used in various sections of the upper facade, especially near the top.
He has painted the stucco of the upper facade and cleaned the tile work.
Last month, after a snowfall and windstorm, a whole section of the upper facade fell to the street, leaving a yawning hole.
A serpent is entwined all along the upper façade around the statue.
The rusticated pilasters of the lower floor are continued above, but become smooth dressed stone to match the upper facade.
In the late 15th century the upper façade was finished and the central nave was vaulted.
There is debate as to when work on the upper façade was completed.
The new building, featuring a rounded upper facade, is to have temperature and humidity controls.
In February 2006, the first phase of a multi-year restoration of the building's upper facade was completed.