Designed by the architect Carlo Maderno, it was completed in 1614. It is 114.69 metres wide and 48 metres high, and has an order of Corinthian columns and pilasters, over which lies an imposing cornice with a central tympanum, crowned by a balustrade with thirteen statues (nearly 6 metres high). An inscription on the entablature commemorates the fact that the façade was built during the pontificate of Pope Paul V Borghese (1605-1621).
In the lower order there are five entrances to the atrium, over which stand nine windows, three of which have a balcony. The central window is the so-called “Benediction Loggia”, where the pope gives his first blessing “urbi et orbi” (to the city and to the world) upon his election and at Christmas and Easter.
The restoration, which ended in July 1999, was aimed at bringing out some whitewashes designed by Maderno, that were hidden under the patina of time.