B. Vatican City
Vatican City, in full State of the Vatican City, Italian Stato della Città del Vaticano, ecclesiastical state, seat of the Roman Catholic Church, and an enclave in Rome, situated on the west bank of the Tiber River. Vatican City is the world’s smallest fully independent nation-state. Its medieval and Renaissance walls form its boundaries except on the southeast at St. Peter’s Square (Piazza San Pietro). Of the six entrances, only three—the piazza, the Arco delle Campane (Arch of the Bells) in the facade of St. Peter’s Basilica, and the entrance to the Vatican Museums and Galleries in the north wall—are open to the public. The most imposing building is St. Peter’s Basilica, built during the 4th century and rebuilt during the 16th century. Erected over the tomb of St. Peter the Apostle, it is the second largest religious building (after Yamoussoukro Basilica) in Christendom.