Why St. Peter's Basilica is special
Basilica di San Pietro is the mother church of the world's 500-million Roman Catholics. This Vatican City house of worship is one of mankind's supreme artistic-architectural accomplishments.

How it evolved
St. Peter's Basilica was erected some 500 years ago over the foundations of the old St. Peter's Basilica, which was built in the 4th century over the tomb of St. Peter.
Many great minds in the first 100 years (beginning in 1506) designed St. Peter's Basilica, yet the composite result is so elegantly harmonious that it seems to be the inspiration of a single genius.
Of all its creators, Michelangelo made the most significant contributions. Not only did he sculpt the graceful Pieta marble statue and design the stunning 133-meter (435-foot) high dome, he served for nearly two decades as the chief architect of St. Peter's Basilica.
Another key contributor was Bernini. He designed the magnificent altar canopy as well as the authoritative St. Peter's frontal facade. The quadruple colonnades that stylishly line St. Peter's Square (actually an ellipse) were also his creation.

What leading travel books say about St. Peter’s Basilica
The massive scale inside St. Peter's is almost too much to absorb.
Italy
Frommer's

St. Peter's is the spiritual heart of Catholicism.
Europe
AAA Travel Books