There are five doors which open into the building. The central is of bronze and one of the few things spared by the destroyer Julius when he demolished the old basilica. The doors next to this are those by which one enters the church. In March 1910 the old and very unhygienic leather flaps were removed, and glazed swing-doors have taken their place. The Porta Santa, or door at the north end of the portico, is walled up. It was only opened for the purpose of celebrating a Jubilee, and has been closed since 1825.
Many and repeated visits are necessary to S. Peter's before the size of the vast interior can be in any way grasped. It is only when one is accustomed to the scale of the little human figures walking about and their insignificance in proportion to the whole, that the immense height of even the Corinthian pilasters of the piers becomes apparent. The roof is vaulted, coffered and gilded. It is supported by four piers on each side of the nave. The floor is of coloured marble, and has the measurements of the great churches of Christendom let in with brass at the spot where each would end if measured from the east. Just inside the central bronze door is a slab of porphyry upon which the emperors were crowned. At the base of each pier, as well as in other parts of the church, the colossal statues of the founders of different religious Orders find a place. The last pier on the right has a bronze figure of S. Peter seated, one foot of which is partially worn away by the lips of devotees.
The dome grows upwards from four massive buttresses. Niches above their bases contain figures of SS. Longinus, Andrew, Helena, and Veronica, who holds the napkin with the impress of the Saviour's Face. Under the dome is the _Confessio_ of S. Peter, to reach which a double flight of steps leads down. Eighty-nine lamps for ever burn on the balustrade which encloses the well of the entrance; and doors of gilded bronze shut off the niche in which the sarcophagus of the Apostle rests. Soaring high up on four bronze columns ninety-four feet from the floor, the great _baldacchino_ rises above all. But so immense is the space under the dome that one has no idea of the height it attains. It was designed by Bernini, and is made partly of the bronze which covered the roof of the Pantheon.