St. Peter's Basilica occupies the central position in Vatican City both physically and culturally. Construction began in 1506 under Pope Julius II and concluded in 1626, spanning 120 years and engaging multiple architects including Donato Bramante, who designed the original plan, and Gian Lorenzo Bernini, who completed the interior and exterior elements. The basilica holds the designation as the world's largest church. The dome, designed principally by Michelangelo, rises 136.57 meters from the floor to the external cross. Beneath the main altar lies the Vatican Necropolis, an ancient burial ground containing what the Catholic Church identifies as St. Peter's Tomb, the believed burial site of the Apostle Peter, first Bishop of Rome, who tradition states was martyred in this area during the first century. Visitors can access the necropolis only through advance-booked guided tours, limited to small groups due to space constraints and preservation requirements. The basilica itself requires no admission fee, though security screening applies to all entrants.
The Sistine Chapel serves as the papal chapel and the location where papal election conclaves occur. Michelangelo Buonarroti painted the ceiling between 1508 and 1512 under commission from Pope Julius II. The ceiling comprises nine central panels depicting scenes from Genesis, surrounded by prophets, sibyls, and ignudi. Michelangelo returned between 1536 and 1541 to paint The Last Judgment on the altar wall. The chapel measures 40.9 meters long and 13.4 meters wide, with the ceiling reaching 20.7 meters at its highest point. Access to the Sistine Chapel occurs only through the Vatican Museums. Photography and speaking above a whisper are prohibited inside due to preservation needs and the chapel's continued liturgical function.
The Vatican Museums comprise multiple collections housed in galleries and rooms that total approximately 7 kilometers of exhibition space. The Pio-Clementine Museum contains classical sculpture, including the Apollo Belvedere and Laocoön and His Sons. The Raphael Rooms consist of four papal apartments frescoed by Raphael Sanzio and his workshop between 1508 and 1524, including The School of Athens. The Gallery of Maps stretches 120 meters and displays 40 topographical maps of Italian regions painted between 1580 and 1583 during the papacy of Gregory XIII. The Pinacoteca, established as a separate gallery in 1932, houses paintings arranged chronologically from the 12th to the 19th centuries. The Niccoline Chapel contains frescoes by Fra Angelico completed between 1447 and 1451. The museums require advance-timed tickets. Wednesday mornings often see partial closures due to papal general audiences.
St. Peter's Square, designed by Gian Lorenzo Bernini and completed in 1667, forms an ellipse 240 meters wide at its broadest point. Two semicircular colonnades, each consisting of four rows of Doric columns, contain 284 columns and 88 pilasters. An Egyptian obelisk, erected in the square's center in 1586, originates from Heliopolis and dates to approximately 1850 BCE, brought to Rome by Emperor Caligula in 37 CE. Two fountains, one designed by Carlo Maderno in 1614 and the other matching it added by Bernini in 1675, flank the obelisk. The square accommodates approximately 300,000 people during major papal events. Papal general audiences occur most Wednesdays at 9:30 AM when the Pope is in residence, requiring free tickets obtained through official Vatican channels or the Prefecture of the Papal Household.
The Vatican Gardens occupy approximately 23 hectares, roughly half of Vatican City's total 0.49 square kilometers. The gardens contain fountains, sculptures, and grottoes developed primarily during the Renaissance and Baroque periods. Access requires a guided tour booked in advance through the Vatican Museums. Tours last approximately two hours and operate in multiple languages. The gardens include a replica of the Lourdes Grotto installed in 1902. The Redemptoris Mater Chapel, completed in 1999, features modern mosaics and serves as the Pope's private chapel. The Vatican Railway Station, completed in 1933, connects via a short rail line to the Italian network, though it operates primarily for freight rather than passenger service.
The Vatican Library, formally the Apostolic Library, holds approximately 1.6 million printed books and 75,000 manuscripts. Established formally in 1475, the library contains texts dating to before the invention of printing, including ancient manuscripts in Greek, Latin, Arabic, and Hebrew. The Vatican Apostolic Archive, separate from the library, houses historical documents of the Holy See. Access to both facilities requires scholarly credentials and advance application. Neither functions as a tourist site. The Swiss Guard, established in 1506 by Pope Julius II, continues to serve as the ceremonial military corps and security force. The 135 guards maintain Swiss citizenship requirements and Catholic faith as prerequisites for service. The distinctive Renaissance-style uniforms, often misattributed to Michelangelo without documentary evidence, date in their current form to the early 20th century.