Rome in early times was surrounded by a wall which bore
the name of its legendary builder, Servius Tullius. The present fortifications
were not constructed until the reign of the emperor Aurelian. The ancient
city was closely built up, with only two great open spaces, in addition to the
Forum. These were the Circus Maximus, in the hollow between the Palatine Mount
and the Aventine, and the Campus Martius, stretching along the Tiber to the
northwest of the Capitoline Hill.
PUBLIC BUILDINGS
Following the map of ancient Rome under the empire we may
note the more important monuments which still exist in something like their
original condition. Across the Tiber and beyond the Campus Martius stands the
mausoleum of Hadrian. The most notable structure in the Campus Martius is
the Pantheon. It is the one ancient building in the entire Roman world
which still survives, inside and out, in a fair state of preservation. The
depression between the Caelian and Esquiline hills contains the Flavian
Amphitheater, better known as the Colosseum. It was begun by Vespasian and
probably completed by Titus. No less than eighty entrances admitted the
forty-five thousand spectators who could be accommodated in this huge
structure. Despite the enormous mass of the present ruins probably two-thirds
of the original materials have been carried away to be used in other buildings.
Close to the Colosseum stands the arch erected by the Senate in honor of
the victory of Constantine over his rival Maxentius. From this event is dated
the triumph of Christianity in the Roman state. The ruins of the huge baths of
Caracalla lie about half a mile from the Colosseum. Near the center of the city
are the remains of the Forum added by Trajan to the accommodations of the
original Forum. It contains the column of Trajan under which that emperor
was buried.