The façade designed by Maderno, is 114.69 metres (376.3 ft) wide and 45.55 metres (149.4 ft) high and is built of travertine stone, with a giant order of Corinthian columns and a central pediment rising in front of a tall attic surmounted by statues of Christ, John the Baptist, and eleven of the apostles. The inscription on the facade reads: IN HONOREM PRINCIPIS APOST PAVLVS V BVRGHESIVS ROMANVS PONT MAX AN MDCXII PONT VII.
In the towers to either side of the facade are two clocks. The clock on the left has been operated electrically since 1931. Its oldest bell dates from 1288.