The drum of the dome, proportionately very high, has eight pairs of double Corinthian pilasters, and in between these are eight large round-headed windows with curved raised lintels above looking rather like eyebrows. The lower story entablature is crowned by a balustrade all the way around which is adorned with eleven free-standing travertine statues of prophets and evangelists, created by many different artists. Left of frame is Trajan's Column.