The Archbasilica of the Most Holy Savior and of Sts. John the Baptist and the Evangelist, better known as St. John Lateran, is the Catholic cathedral of the Diocese of Rome – making it the official seat of its bishop, Pope Francis. It is the oldest of the four papal basilicas and stands over the ruins of a Roman cavalry fort. From the 4th to the 14th century, St. John Lateran was the seat of the papacy, thus becoming the symbol and the heart of the Church’s life. It was also the site of the original Holy Door. Today, online visitors can take a virtual reality tour of the world’s only archbasilica on the Vatican’s website or see it in one of countless online video tours.