Vatican City:The independent city-state that serves as the headquarters of the Catholic Church and the residence of the Pope.
Papal Basilica: A designation given to certain churches that hold special ceremonial and historical significance for the Catholic Church, of which St. Peter's Basilica is one.
Renaissance Architecture: The architectural style that heavily influenced the design and construction of St. Peter's Basilica, characterized by its grand, symmetrical, and classically-inspired features.