Rome
How Rome was built and evolved over time
Rome was built, demolished and rebuilt out of itself, and the method is visible everywhere.
Roman concrete. The Romans mixed lime with pozzolana, the volcanic ash from the Alban Hills, producing a concrete that sets underwater, gains strength with age and could be poured into shapes that cut stone cannot reach. It is the reason the Pantheon's dome still stands unreinforced.
Facing. The concrete core was faced in brick or small stone and then, on important buildings, clad in marble and travertine. The Colosseum's pockmarks are the holes left where the iron cramps holding that cladding were later dug out.
The fire that rebuilt the city. During the reign of Nero, two-thirds of Rome was ruined in the Great Fire. A city that burns to that extent is not repaired but replanned, and what rose afterwards did so on a scale and to a street pattern the fire had made possible.
The sack that did not. Rome was sacked in by the Visigoths under Alaric I, and very little physical damage was done, most of which was repaired. What could not be replaced was portable — artwork in precious metals, household goods. The popular picture of 410 as the moment the city fell down is wrong, and the buildings are the evidence.
Spoliation. For a thousand years, ancient Rome was the quarry for medieval and papal Rome. Columns were carried into churches, marble was burned for lime, and travertine was lifted from monuments that had no defender.
Reuse. The Pantheon survived because it became a church in . Piazza Navona keeps the shape of Domitian's stadium because houses were built on the seating. The surest way for an ancient building to last here was to be given a new job.
Then four hundred years of one continuous programme. Beginning with the Renaissance, almost every pope from Nicholas V (1447–1455) onward pursued a coherent architectural and urban programme aimed at making Rome the artistic and cultural centre of the world. Under the popes from Pius IV to Sixtus V the city became the centre of a reformed Catholicism and filled with new monuments celebrating the papacy; the popes and cardinals of the seventeenth and early eighteenth centuries carried it on in Baroque. Most of what a visitor walks through between the Pantheon and St Peter's is this campaign, not the ancient one.
Obelisks. Thirteen ancient Egyptian obelisks stand in Rome, more than in Egypt — brought as imperial trophies, buried and forgotten, then dug up and re-erected as the punctuation of that papal street plan.
The nineteenth century. Unification in brought ministries, the Tiber embankments and the vast Victor Emmanuel monument that Romans have never forgiven.
And then the centre was cut open. Mussolini demolished fairly large parts of the city centre to drive wide avenues and squares through it, intended to celebrate the regime and the glorification of classical Rome. The clearances are why some ancient monuments now stand isolated in traffic rather than embedded in the city that had grown around them.
The war mostly spared it, and once did not. Rome largely escaped the fate of other European cities because of its art and the presence of the Vatican. The exception was , when Allied bombing of the San Lorenzo district killed about 3,000 people and injured 11,000.