In the course of centuries, several pontifices added spaces, decorations and works of art. An interior restoration was made by Borromini, according to Innocenzo X's will, on the Jubilee occasion in 1650. The basilica's imposing façade, made out of travertine, overlooks "Piazza di Porta San Giovanni" and was constructed in 1735 by Alessandro Galilei, a famous architect. Pio IX and Leone XIII had reconstruction and restoration works executed in its presbytery and apse by Virginio Vespignani.
On its balustrade you can admire 15 gigantic statues (7 metres high) representing Saints and the Redeemer's one being the central of them. In its left porch, you can see the Constantine's statue coming from the "Terme Imperiali del Quirinale". The great central door, through which you can enter this basilica, has precious bronze leaves. The last door on the right, is the Holy Door which, like Saint Peter's one, is open only on the Jubilees occasion. Inside, this church has five aisles and a Latin cross structure, is wide and solemn and no less than 130 metres long. Its sumptuous golden ceiling and its beautiful floor, which recalls the style of the Cosmati Family, represent a sure attraction for visitors. At the end of the greatest nave, under the great triumphal arch, you can admire the papal altar, with the imposing and elegant tabernacle dating back to the second half of the IV century; in it, you can see frescoes attributed to Barna from Siena. Besides, the relics of Saint Peter and Paul' heads are kept in precious silver containers. Among the great complex of statues, monuments and decorations, we point out (in the nave, behind the first pillar on the right) the fragment of the famous fresco by Giotto, representing Bonifacio VIII while announces the Jubilee in 1300.