Columbia subject headings:
Harvard subject headings:
Basilica di San Pietro in Vaticano.
Peter, the Apostle, Saint--Relics--Vatican City.
Peter, the Apostle, Saint--Tomb.
Princeton subject headings:
Basilica di San Pietro in Vaticano.
Christian antiquities--Italy--Rome.
Excavations (Archaeology)--Italy--Rome.
Peter, the Apostle, Saint--Relics--Italy--Rome.
Peter, the Apostle, Saint--Tomb.
Rome (Italy)--Antiquities.