Rising massive and beautiful, in the square of the same name, is one of the oldest churches in the world, the Basilica of St. John in Lateran, the cathedral of Rome. Erected on the remains of a previous fourth-century AD building, during the imperial reign of Constantine, the church underwent considerable rebuilding over the centuries, including the last two in order of time by Francesco Borromini in 1646, when for Innocent X, the five naves were renewed, and that by Alessandro Galilei, who in 1735 gave the façade its present solemn appearance. Spaced by a majestic order of pilasters and columns, the imposing front in travertine has an portico with architraves containing five portals, including the Porta Santa, opened only in Jubilee years and, high up an arched loggia, crowned by a trabeation with a central tympanum, and by an elaborate balustrade adorned by 15 colossal statues. The sumptuous interior on a Latin cross, a good 130 m. long, with its five wide naves, divided by columns and richly decorated with stucco and gilt work, its amazing gilded ceiling and magnificent cosmatesque paving, contains fine frescos, a great number of statues, paintings, mosaics, reliefs and monuments of exquisite workmanship. Among the many masterpieces are the papal altar located at the end of the central nave, with its slender and elegant ogival tabernacle, dating from the second half of the fourteenth century, containing the reliquiae of the heads of St. Peter and St. Paul in a precious silver urn, a fragment of a Giotto fresco, depicting Boniface VIII and, in the apse, a valuable mosaic made in 1291 by the Franciscan friar Jacopo Torriti. Annexed to the building is the atmospheric thirteenth-century cloister, designed by Vassalletto, containing interesting architectonic fragments from the earliest basilica, as well as early-Christian inscriptions, sculptures and relief work. Finally, on the square in front of the basilica soars the tallest obelisk in Rome, 46m. high, transported to the city by Constant II in 357 AD.