St. Peter's Basilica is big! It is, indeed, the biggest church in the world. Even today, it would be a major construction project; 400 years ago, it must have been phenomenonal.
The initial basilica was built by the emperor Constantine when Christianity became the official state religion, towards the end of the 3rd century. Advancing years and the neglect while the papacy was in Avignon for 73 years resulted in the old building being beyond repair.
Pope Nicolas V (1447 - 1455) decided to rebuild, and gave the project to Rossellino, but work was suspended upon the Pope's death. Thus it was Pope Julius II (1503 - 1513) who gave the contract to Bramante to design and build the current building, which took 176 years! A succession of architects, including Raphael and Antonio da Sagnallo the Younger were involved, until finally Michelangelo, then almost 70 years old, designed the dome. Work continued according to his plans after his death following the original Greek Cross design. But Pope Paul V (1605 - 1621) had the architect Maderno switch to a Latin Cross design.
The facade was part of Maderno's design.
Looking from the front of the Basilica towards the Tiber, showing Bernini's Colonnade. The semi-circular section presents a welcoming appearance, indicating the welcoming open hands of Mother Church. Bernini also designed the statues of the 140 saints along the top of the Colonnade. The platform in the middle is for the altar used when Mass is celebrated outdoors, such as for the canonisation.
The Portico, with St. Peter's Square off to the left, and the inside of the Basilica on the right.
The outside of the Holy Door, opened every 25 years on Christmas Eve, and open for one year.
Inside view of the Holy Door.
Final Gallery